Solved papers for JEE Main & Advanced Physics Current Electricity, Charging & Discharging Of Capacitors / वर्तमान बिजली, चार्ज और कैपेसिटर का निर JEE PYQ-Current Electricity Charging and Discharging of Capacitors

done JEE PYQ-Current Electricity Charging and Discharging of Capacitors Total Questions - 169

• question_answer1) If an ammeter is to be used in place of a voltmeter, then we must connect with the ammeter a  [AIEEE 2002]
  A)
  low resistance in parallel
  done clear
  B)
  high resistance in parallel
  done clear
  C)
  high resistance in series
  done clear
  D)
  low resistance in series
  done clear
  View Answer play_arrow

• question_answer2) A wire when connected to 220 V mains supply has power dissipation \[{{P}_{1}}\]. Now, the wire is cut into two equal pieces which are connected in parallel to the same supply. Power dissipation in this case is \[{{P}_{2}}\]. Then, \[{{P}_{2}}:{{P}_{1}}\] is   [AIEEE 2002]
  A)
  1
  done clear
  B)
  4
  done clear
  C)
  2
  done clear
  D)
  3
  done clear
  View Answer play_arrow

• question_answer3) 

  If in the circuit, power dissipation is 150 W, then R is                                          [AIEEE 2002]

  A)
  \[2\,\,\Omega \]
  done clear
  B)
  \[6\,\,\Omega \]
  done clear
  C)
  \[5\,\,\Omega \]
  done clear
  D)
  \[4\,\,\Omega \]
  done clear
  View Answer play_arrow

• question_answer4) At absolute zero, Si acts as          [AIEEE 2002]
  A)
  non-metal
  done clear
  B)
  metal
  done clear
  C)
  insulator
  done clear
  D)
  None of these
  done clear
  View Answer play_arrow

• question_answer5) If \[{{\theta }_{i}}\] is the inversion temperature, \[{{\theta }_{n}}\] is the neutral temperature, \[{{\theta }_{c}}\] is the temperature of the cold junction, then                   [AIEEE 2002]
  A)
  \[{{\theta }_{i}}+{{\theta }_{c}}={{\theta }_{n}}\]
  done clear
  B)
  \[{{\theta }_{i}}-{{\theta }_{c}}=2{{\theta }_{n}}\]
  done clear
  C)
  \[\frac{{{\theta }_{i}}+{{\theta }_{c}}}{2}={{\theta }_{n}}\]
  done clear
  D)
  \[{{\theta }_{c}}-{{\theta }_{i}}=2{{\theta }_{n}}\]
  done clear
  View Answer play_arrow

• question_answer6) By increasing the temperature, the specific resistance of a conductor and a semiconductor,
  A)
  increases for both           
  done clear
  B)
  decreases for both
  done clear
  C)
  increases and decreases, respectively
  done clear
  D)
  decreases and increases, respectively
  done clear
  View Answer play_arrow

• question_answer7) The mass of a product liberated on anode in an 'electrochemical cell depends on (where t is the time period for which the current is passed)                            [AIEEE 2002]
  A)
  \[{{(lt)}^{1/2}}\] 
  done clear
  B)
  \[lt\]
  done clear
  C)
  \[l/t\]
  done clear
  D)
  \[{{l}^{2}}t\]
  done clear
  View Answer play_arrow

• question_answer8) The length of a wire of a potentiometer is 100 cm and the emf of its stand and cell is. E volt. It is employed to measure the emf of a battery whose internal resistance is \[0.5\,\,\Omega \]. If the balance point is obtained at \[1=30\] cm from the positive end, the emf of the battery is               [AIEEE 2003]
  A)
  \[\frac{30\,E}{100.5}\]
  done clear
  B)
  \[\frac{30\,E}{100-05}\]
  done clear
  C)
  \[\frac{30\,(E-0.5i)}{100}\], where \[i\] is the current in the potentiometer wire                                   
  done clear
  D)
  \[\frac{30\,E}{100}\]
  done clear
  View Answer play_arrow

• question_answer9) A strip of copper and another of germanium are cooled from room temperature to 80 K. The resistance of [AIEEE 2003]
  A)
  each of these decreases
  done clear
  B)
  copper strip increases and that of germanium decreas.es
  done clear
  C)
  copper strip decreases and that of germanium increases
  done clear
  D)
  each of the above increases
  done clear
  View Answer play_arrow

• question_answer10) The thermo-emf of a thermocouple is \[25\mu V{{/}^{o}}C\] at room temperature. A galvanometer of \[40\,\Omega \]. resistance, capable of detecting current as low as \[{{10}^{-5}}\] A, is   connected with the thermocouple. The smallest temperature difference that can be detected by this system is [AIEEE 2003]
  A)
  \[{{16}^{o}}C\]
  done clear
  B)
  \[{{12}^{o}}C\]
  done clear
  C)
  \[{{8}^{o}}C\]
  done clear
  D)
  \[{{20}^{o}}C\] 
  done clear
  View Answer play_arrow

• question_answer11) The negative Zn-pole of Daniell cell, sending a constant current through a circuit, decreases in mass by \[0.13\]g in 30 min. If the electrochemical equivalent of Zn and Cu are \[32.5\] and \[31.5\] respectively, the increase in the mass of the positive Cu-pole in this time is         AIEEE 2003]
  A)
  \[0.180\] g
  done clear
  B)
  \[0.141\] g         
  done clear
  C)
  \[0.126\]g
  done clear
  D)
  \[0.242\] g
  done clear
  View Answer play_arrow

• question_answer12) The difference in the variation of resistance with temperature in a metal and a semiconductor arises essentially due to the difference in the [AIEEE 2003]
  A)
  crystal structure
  done clear
  B)
  variation of the number of charge carriers with temperature
  done clear
  C)
  type of bonding
  done clear
  D)
  variation of scattering mechanism with temperature
  done clear
  View Answer play_arrow

• question_answer13) An ammeter reads upto 1 A. Its internal resistance is \[0.81\,\,\Omega \]. To increase the range to 10 A, the value of the required shunt is [AIEEE 2003]
  A)
  \[0.03\,\,\Omega \]
  done clear
  B)
  \[0.3\,\,\Omega \]
  done clear
  C)
  \[0.9\,\,\Omega \]
  done clear
  D)
  \[0.09\,\,\Omega \]
  done clear
  View Answer play_arrow

• question_answer14) 

  A 3 V battery with negligible internal resistance is connected in a circuit as shown in the figure. The current I, in the circuit will be      [AIEEE 2003]

  A)
              1 A
  done clear
  B)
  \[1.5\] A  
  done clear
  C)
              2 A
  done clear
  D)
  1 A
  done clear
  View Answer play_arrow

• question_answer15) A 220 V, 1000 W bulb is connected across a 110 V mains supply. The power consumed will be [AIEEE 2003]
  A)
  750 W
  done clear
  B)
  500 W
  done clear
  C)
  250W
  done clear
  D)
  1000 W
  done clear
  View Answer play_arrow

• question_answer16) The length of a given cylindrical wire is increased by \[100%\]. Due to the consequent decrease in diameter, the change in the resistance of the wire will be                                             [AIEEE 2003]
  A)
  \[200%\]
  done clear
  B)
  \[100%\]
  done clear
  C)
  \[50%\]
  done clear
  D)
  \[300%\] 
  done clear
  View Answer play_arrow

• question_answer17) 

  The total current supplied to the circuit by the battery is                              [AIEEE 2004]

  A)
  1A
  done clear
  B)
  2A
  done clear
  C)
  4A
  done clear
  D)
  6A
  done clear
  View Answer play_arrow

• question_answer18) The resistance of the series combination of two resistances is S. When they are joined in parallel, the total resistance is P. If\[S=nP,\] then the minimum possible value of n is   [AIEEE 2004]
  A)
  4
  done clear
  B)
  3      
  done clear
  C)
  2
  done clear
  D)
  1
  done clear
  View Answer play_arrow

• question_answer19) An electric current is passed through a circuit containing two wires of the same material, connected in parallel. If the lengths and radii of the wires are in the ratio of 4/3 and 2/3, then the ratio of the currents passing through the wire will be                                         [AIEEE 2004]
  A)
  3
  done clear
  B)
  1/3
  done clear
  C)
  8/9
  done clear
  D)
  2         
  done clear
  View Answer play_arrow

• question_answer20) In a metre bridge experiment, null point is obtained at 20 cm from one end of the wire when resistance\[X\]is balanced against another resistance\[Y\].If\[X<Y,\]then where will be the new position of the null point from the same end, if one decides to balance a resistance of \[4X\]against\[Y\]?                         [AIEEE 2004]
  A)
  50 cm
  done clear
  B)
  80 cm
  done clear
  C)
  40 cm
  done clear
  D)
  70 cm
  done clear
  View Answer play_arrow

• question_answer21) The thermistors are usually made of [AIEEE 2004]
  A)
  metals with low temperature coefficient of resistivity
  done clear
  B)
  metals with high temperature coefficient of resistivity
  done clear
  C)
  metal oxides with high temperature coefficient of resistivity
  done clear
  D)
  semiconducting   materials   having   low temperature coefficient of resistivity
  done clear
  View Answer play_arrow

• question_answer22) Time taken by a 836 W heater to heat one litre of water from\[10{}^\circ C\]to\[40{}^\circ C\]is     [AIEEE 2004]
  A)
  50s
  done clear
  B)
  100s
  done clear
  C)
  150s
  done clear
  D)
  200s
  done clear
  View Answer play_arrow

• question_answer23) The thermo-emf of a thermocouple varies with the temperature\[\theta \]of the hot junction as\[E=a\theta +b{{\theta }^{2}}\]in volts where the ratio a/b is\[700{}^\circ C\]. If the cold junction is kept at\[0{}^\circ C,\]then the neutral temperature is           [AIEEE 2004]
  A)
  \[700{}^\circ C\]          
  done clear
  B)
       \[350{}^\circ C\]
  done clear
  C)
  \[1400{}^\circ C\]
  done clear
  D)
  no neutral temperature is possible for this thermocouple
  done clear
  View Answer play_arrow

• question_answer24) The electrochemical equivalent of metal is\[3.3\times {{10}^{-7}}\,kg/C\]. The mass of the metal liberated at the cathode when a 3 A current is passed for 2 s, will be                   [AIEEE 2004]
  A)
  \[19.8\times {{10}^{-7}}kg\]
  done clear
  B)
  \[9.9\times {{10}^{-7}}kg\]
  done clear
  C)
  \[6.6\times {{10}^{-7}}kg\]
  done clear
  D)
  \[1.1\times {{10}^{-7}}kg\]
  done clear
  View Answer play_arrow

• question_answer25) A piece of copper and another of germanium are cooled from room temperature to 77 K, the resistance of                                 [AIEEE 2004]
  A)
  each of them increases
  done clear
  B)
  each of them decreases
  done clear
  C)
  copper decreases and germanium increases
  done clear
  D)
  copper increases and germanium decreases
  done clear
  View Answer play_arrow

• question_answer26) A moving coil galvanometer has 150 equal divisions. Its current sensitivity is 10 divisions per milliampere and voltage sensitivity is 2 divisions per millivolt. In order that each division reads 1 V, the resistance in Ohm's needed to be connected in series with the coil will be [AIEEE 2005]
  A)
  \[{{10}^{3}}\]
  done clear
  B)
  \[{{10}^{5}}\]
  done clear
  C)
  99995
  done clear
  D)
  9995
  done clear
  View Answer play_arrow

• question_answer27) Two voltameters, one of copper and another of silver, are joined in parallel. When a total charge q flows through the voltameters, equal amount of metals are deposited.   If   the   electrochemical equivalents of copper and silver are\[{{z}_{1}}\]and\[{{z}_{2}}\]respectively, the charge which flows through the silver voltameter is [AIEEE 2005]
  A)
  \[\frac{q}{1+\frac{{{z}_{1}}}{{{z}_{2}}}}\]
  done clear
  B)
  \[\frac{q}{1+\frac{{{z}_{2}}}{{{z}_{1}}}}\]
  done clear
  C)
  \[q\frac{{{z}_{1}}}{{{z}_{2}}}\]          
  done clear
  D)
  \[q\frac{{{z}_{2}}}{{{z}_{1}}}\]
  done clear
  View Answer play_arrow

• question_answer28) 

  In the circuit, the galvanometer G shows zero deflection. If the batteries A and B have negligible internal resistance, the value of the resistor R will be                            [AIEEE 2005]

  A)
  \[200\,\Omega \]
  done clear
  B)
  \[100\,\Omega \]
  done clear
  C)
  \[500\,\Omega \]
  done clear
  D)
  \[1000\,\Omega \]
  done clear
  View Answer play_arrow

• question_answer29) Two sources of equal emf are connected to an external resistance R. The internal resistances of the two sources are\[{{R}_{1}}\]and\[{{R}_{2}}({{R}_{2}}>{{R}_{1}})\].   If   the   potential difference across the source having internal resistance\[{{R}_{2}}\]is zero, then          [AIEEE 2005]
  A)
  \[R=\frac{{{R}_{2}}({{R}_{1}}+{{R}_{2}})}{({{R}_{2}}-{{R}_{1}})}\]
  done clear
  B)
  \[R={{R}_{2}}-{{R}_{1}}\]
  done clear
  C)
  \[R=\frac{{{R}_{1}}{{R}_{2}}}{({{R}_{1}}+{{R}_{2}})}\]
  done clear
  D)
  \[R=\frac{{{R}_{1}}{{R}_{2}}}{({{R}_{2}}-{{R}_{1}})}\]
  done clear
  View Answer play_arrow

• question_answer30) A heater coil is cut into two equal parts and only one part is now used in the heater. The heat generated will now be                   [AIEEE 2005]
  A)
  doubled
  done clear
  B)
  four times
  done clear
  C)
  one-fourth
  done clear
  D)
  halved
  done clear
  View Answer play_arrow

• question_answer31) An energy source will supply a constant current into the load, if its internal resistance is [AIEEE 2005]
  A)
  equal to the resistance of the load
  done clear
  B)
  very large as compared to the load resistance
  done clear
  C)
  zero
  done clear
  D)
  non-zero but less than the resistance of the load
  done clear
  View Answer play_arrow

• question_answer32) In a potentiometer experiment, the balancing with a cell is at length 240 cm. On shunting the cell with a resistance of Q, the balancing length becomes 120 cm. The internal resistance of the cell is [AIEEE 2005]
  A)
  \[1\,\Omega \]
  done clear
  B)
  \[0.5\,\Omega \]
  done clear
  C)
  \[4\,\Omega \]
  done clear
  D)
  \[2\,\Omega \]
  done clear
  View Answer play_arrow

• question_answer33) The resistance of hot tungsten filament is about 10 times the cold resistance. What will be the resistance of 100 W and 200 V lamp, when not in use?                                       [AIEEE 2005]
  A)
  \[40\,\Omega \]
  done clear
  B)
  \[20\,\Omega \]
  done clear
  C)
  \[400\,\Omega \]
  done clear
  D)
  \[200\,\Omega \]
  done clear
  View Answer play_arrow

• question_answer34) The Kirchhoff’s first law\[(\Sigma i=0)\]and second law\[(\Sigma iR=\Sigma E)\], where the symbols have their usual meanings, are respectively based on [AIEEE 2006]
  A)
  Conservation of charge, conservation of momentum
  done clear
  B)
  Conservation of energy, conservation of charge
  done clear
  C)
  Conservation of momentum, conservation of charge
  done clear
  D)
  Conservation of charge, conservation of energy
  done clear
  View Answer play_arrow

• question_answer35) A material B has twice the specific resistance of A. A circular wire made of B has twice the diameter of a wire made of Then, for the two wires to .have the same resistance, the ratio\[{{I}_{B}}/{{I}_{A}}\]respective lengths must be [AIEEE 2006]
  A)
  1
  done clear
  B)
  \[\frac{1}{2}\]    
  done clear
  C)
  \[\frac{1}{4}\]
  done clear
  D)
  2
  done clear
  View Answer play_arrow

• question_answer36) A thermocouple is made of two metals, Antimony and Bismuth. If one junction of the couple is kept hot and the other is kept cold, then an electric current will         [AIEEE 2006]
  A)
  flow from Antimony to Bismuth at the hot junction
  done clear
  B)
  flow from Bismuth to Antimony at the cold junction
  done clear
  C)
  not flow through the thermocouple
  done clear
  D)
  flow from Antimony to Bismuth at the cold junction
  done clear
  View Answer play_arrow

• question_answer37) 

  The current I drawn from the 5 V source will  be [AIEEE 2006]

  A)
  0.33 A
  done clear
  B)
  0.5 A
  done clear
  C)
  0.67 A
  done clear
  D)
  0.17 A
  done clear
  View Answer play_arrow

• question_answer38) The resistance of a bulb filament is\[100\text{ }\Omega \].at a temperature of \[100{}^\circ C\]. If its temperature coefficient of resistance is \[0.005/{}^\circ C,\] its resistance will become\[200\,\Omega \]. at a temperature of                                             [AIEEE 2006]
  A)
  \[300{}^\circ C\]
  done clear
  B)
  \[400{}^\circ C\]
  done clear
  C)
  \[500{}^\circ C\]
  done clear
  D)
  \[200{}^\circ C\]
  done clear
  View Answer play_arrow

• question_answer39) In a Wheatstone’s bridge, three resistances P, Q and R are connected in the three arms and the fourth arm is formed by two resistances\[{{S}_{1}}\]and\[{{S}_{2}}\]connected in parallel. The condition for the bridge to be balanced will be      [AIEEE 2006]
  A)
  \[\frac{P}{Q}=\frac{2R}{{{S}_{1}}+{{S}_{2}}}\]
  done clear
  B)
  \[\frac{P}{Q}=\frac{R({{S}_{1}}+{{S}_{2}})}{{{S}_{1}}{{S}_{2}}}\]
  done clear
  C)
  \[\frac{P}{Q}=\frac{R({{S}_{1}}+{{S}_{2}})}{2{{S}_{1}}{{S}_{2}}}\]
  done clear
  D)
  \[\frac{P}{Q}=\frac{R}{{{S}_{1}}+{{S}_{2}}}\]
  done clear
  View Answer play_arrow

• question_answer40) 

  The circuit has two oppositely connected ideal diodes in parallel. What is the current flowing in the circuit? [AIEEE 2006]

  A)
  1.71 A
  done clear
  B)
  2.00 A
  done clear
  C)
  2.31 A
  done clear
  D)
  1.33 A
  done clear
  View Answer play_arrow

• question_answer41) An electric bulb is rated\[220\text{ }V-100\text{ }W\]The power consumed by it when operated on 110 V will be                                          [AIEEE 2006]
  A)
  75 W
  done clear
  B)
  40 W  
  done clear
  C)
  25 W
  done clear
  D)
  50 W
  done clear
  View Answer play_arrow

• question_answer42) The resistance of a wire is\[\int_{\sqrt{2}}^{x}{\frac{dt}{t\sqrt{{{t}^{2}}-1}}}=\pi /2\]at\[\pi \]and \[\sqrt{3}/2\],at\[2\sqrt{2}\] The resistance of the wire at \[\int{\frac{dx}{\cos x+\sqrt{3}\sin x}}\] will be                    [AIEEE 2007]
  A)
  \[\frac{1}{2}\log \tan \left( \frac{x}{2}+\frac{\pi }{12} \right)+C\]
  done clear
  B)
  \[\frac{1}{2}\log \tan \left( \frac{x}{2}-\frac{\pi }{12} \right)+C\]
  done clear
  C)
  \[\log \tan \left( \frac{x}{2}+\frac{\pi }{12} \right)+C\]
  done clear
  D)
  \[\log \tan \left( \frac{x}{2}-\frac{\pi }{12} \right)+C\]
  done clear
  View Answer play_arrow

• question_answer43) 

  A 5V battery with internal resistance \[2\,\Omega \] and a 2V battery with internal resistance \[1\,\Omega \] are connected to a \[10\,\,\Omega \] resistor as shown in the figure. The current in the \[10\,\,\Omega \] resistor is            [AIEEE 2008]

  A)
  0.03 A \[{{P}_{2}}\] to \[{{P}_{1}}\]
  done clear
  B)
  0.27 A \[{{P}_{1}}\] to \[{{P}_{2}}\]
  done clear
  C)
  0.27 A \[{{P}_{2}}\] to \[{{P}_{1}}\]
  done clear
  D)
  0.03 A \[{{P}_{1}}\] to \[{{P}_{2}}\]
  done clear
  View Answer play_arrow

• question_answer44) 

  Shown in the figure is a meter-bridge set up with null deflection in the galvanometer. The value of the unknown resistor R is            [AIEEE 2008]

  A)
  110 \[\Omega \]
  done clear
  B)
  55 \[\Omega \]
  done clear
  C)
  13.75 \[\Omega \]
  done clear
  D)
  220 \[\Omega \]
  done clear
  View Answer play_arrow

• question_answer45) 

  STATEMENT - 1

  The temperature dependence of resistance is usually given as\[R={{R}_{0}}(1+\alpha \,\,\Delta t)\]. The resistance of a wire changes from\[100\,\Omega \]to \[150\,\Omega \] when its temperature is increased from \[27{}^\text{o}C\] to \[227{}^\text{o}C.\] This implies that\[\alpha =2.5\]\[\times {{10}^{3}}/{}^\text{o}C.\]

  STATEMENT - 2 \[R={{R}_{0}}(1+\alpha \text{ }\Delta t)\]is valid only when the change in the temperature \[\Delta T\] is small and\[\Delta R=(R{{R}_{0}})<<{{R}_{0}}.\] [AIEEE 2009]

  A)
              Statement - 1 is True, Statement - 2 is False.
  done clear
  B)
  Statement - 1 is True, Statement - 2 is True; Statement - 2 is a correct explanation for Statement - 1.
  done clear
  C)
  Statement - 1 is True, Statement - 2 is True; Statement - 2 is not the correct explanation for Statement - 1.
  done clear
  D)
  Statement - 1 is False, Statement - 2 is True.         
  done clear
  View Answer play_arrow

• question_answer46) Two conductors have the same resistance at \[0{}^\circ C\]but their temperature coefficients of resistance are\[{{\alpha }_{1}}\]and\[{{\alpha }_{2}}\]. the respective temperature coefficients of their series and parallel combinations are nearly - [AIEEE 2010]
  A)
  \[\frac{{{\alpha }_{1}}+{{\alpha }_{2}}}{2},\frac{{{\alpha }_{1}}+{{\alpha }_{2}}}{2}\]
  done clear
  B)
  \[\frac{{{\alpha }_{1}}+{{\alpha }_{2}}}{2},{{\alpha }_{1}}+{{\alpha }_{2}}\]
  done clear
  C)
  \[{{\alpha }_{1}}+{{\alpha }_{2}},\frac{{{\alpha }_{1}}+{{\alpha }_{2}}}{2}\]
  done clear
  D)
  \[{{\alpha }_{1}}+{{\alpha }_{2}},\frac{{{\alpha }_{1}}{{\alpha }_{2}}}{{{\alpha }_{1}}+{{\alpha }_{2}}}\]
  done clear
  View Answer play_arrow

• question_answer47) A resistor 'R' and \[2\mu F\] capacitor in series is connected through a switch to 200 V direct supply. Across the capacitor is a neon bulb that lights up at 120 V. Calculate the value of R to make the bulb light up 5 s after the switch has been closed. (\[{{\log }_{10}}2.5=0.4\])     [AIEEE 2011]
  A)
  \[3.3\times {{10}^{7}}\Omega \]
  done clear
  B)
  \[1.3\times {{10}^{4}}\Omega \]
  done clear
  C)
  \[1.7\times {{10}^{5}}\Omega \]
  done clear
  D)
  \[2.7\times {{10}^{6}}\Omega \]
  done clear
  View Answer play_arrow

• question_answer48) If a wire is stretched to make it 0.1% longer, its resistance will                                  [AIEEE 2011]
  A)
  Decrease by 0.05%
  done clear
  B)
  Increase by 0.05%
  done clear
  C)
  Increase by 0.2%
  done clear
  D)
  Decrease by 0.2%
  done clear
  View Answer play_arrow

• question_answer49) The current in the primary circuit of a potentiometer is 0.2 A. The specific resistance and cross-section of the potentiometer wire are \[4\times {{10}^{-7}}\]ohm metre and \[8\times {{10}^{-7}}{{m}^{2}}\]respectively. The potential gradient will be equal to:            [AIEEE 11-05-2011]
  A)
  1 V/ m
  done clear
  B)
  0.5 V/m            
  done clear
  C)
  0.1 V/m
  done clear
  D)
  0.2 V/m
  done clear
  View Answer play_arrow

• question_answer50) Combination of two identical capacitors, a resistor R and a dc voltage source of voltage 6V is used in an experiment on a (C - R) circuit. It is found that for a parallel combination of the capacitor the time in which the voltage of the fully charged combination reduces to half its original voltage is 10 second. For series combination the time needed for reducing the voltage of the fully charged series combination by half is:  [AIEEE 11-05-2011]
  A)
  10 second
  done clear
  B)
  5 second         
  done clear
  C)
  2.5 second
  done clear
  D)
  20 second
  done clear
  View Answer play_arrow

• question_answer51) 

  The figure shows an experimental plot discharging of a capacitor in an RC circuit. The time constant \[\tau \] of this circuit lies between: [AIEEE 2012]

  A)
  150 sec and 200 sec       
  done clear
  B)
  0 and 50 sec
  done clear
  C)
  50 sec and 100 sec         
  done clear
  D)
  100 sec and 150 sec
  done clear
  View Answer play_arrow

• question_answer52) Two electric bulbs marked 25W- 220V and 100W - 220 V are connected in series to a 440 V supply. Which of the bulbs will fuse?            [AIEEE 2012]
  A)
  both     
  done clear
  B)
  100W
  done clear
  C)
  25W
  done clear
  D)
  neither 
  done clear
  View Answer play_arrow

• question_answer53) A resistance R and a capacitance C are connected in series to a battery of negligible internal resistance through a key. The key is closed at t = If after t sec the voltage across the capacitance was seven times the voltage across R, the value of t is [JEE ONLINE 12-05-2012]
  A)
  \[3RC\ell n2\]
  done clear
  B)
  \[2RC\,\ell n2\]
  done clear
  C)
  \[2RC\,\ell n7\]
  done clear
  D)
  \[3RC\,\ell n7\]
  done clear
  View Answer play_arrow

• question_answer54) Three resistors of \[4\Omega ,6\Omega \]and \[12\Omega \]are connected in parallel and the combination is connected in series with a 1.5 V battery of\[1\Omega \]internal resistance. The rate of Joule heating in the \[4\Omega \]resistor is [JEE ONLINE 12-05-2012]
  A)
  0.55W
  done clear
  B)
  0.33 W
  done clear
  C)
  0.25 W
  done clear
  D)
  0.86 W
  done clear
  View Answer play_arrow

• question_answer55) 

  It is preferable to measure the e.m.f. of a cell by potentiometer than by a voltmeter because of the following possible reasons.                                 [JEE ONLINE 12-05-2012]

  (i) In case of potentiometer, no current flows through the cell.

  (ii) The length of the potentiometer allows greater precision.

  (iii) Measurement by the potentiometer is quicker.

  (iv) The sensitivity of the galvanometer, when using a potentiometer is not relevant.

  Which of these reasons are correct?

  A)
  (i), (iii), (iv)
  done clear
  B)
  (i), (iii), (iv)
  done clear
  C)
  (i),(ii)
  done clear
  D)
  (i), (ii), (iii), (iv)
  done clear
  View Answer play_arrow

• question_answer56) In a sensitive meter bridge apparatus the bridge wire should possess [JEE ONLINE 12-05-2012]
  A)
  high resistivity and low temperature coefficient.
  done clear
  B)
  low resistivity and high temperature coefficient.
  done clear
  C)
  low resistivity and low temperature coefficient.
  done clear
  D)
  high resistivity and high temperature coefficient.
  done clear
  View Answer play_arrow

• question_answer57) 

  A 6.0 volt battery is connected to two light bulbs as shown in figure. Light bulb 1 has resistance 3 ohm while light bulb 2 has resistance 6 ohm.

  Battery has negligible internal resistance. Which bulb will glow brighter? [JEE ONLINE 19-05-2012]

  A)
  Bulb 1 will glow more first and then its brightness will become less than bulb 2
  done clear
  B)
  Bulb 1
  done clear
  C)
  Bulb 2
  done clear
  D)
  Both glow equally
  done clear
  View Answer play_arrow

• question_answer58) The resistance of a wire is R. It is bent at the middle by 180° and both the ends are twisted together to make a shorter wire. The resistance of the new wire is [JEE ONLINE 26-05-2012]
  A)
  2R
  done clear
  B)
  R/2
  done clear
  C)
  R/4
  done clear
  D)
  R/S
  done clear
  View Answer play_arrow

• question_answer59) In an experiment of potentiometer for measuring the internal resistance of primary cell a balancing length \[\ell \]is obtained on the potentiometer wire when the cell is open circuit. Now the cell is short circuited by a resistance R, If R is to be equal to the internal resistance of the cell the balancing length on the potentiometer wire will be                  [JEE ONLINE 26-05-2012]
  A)
  \[\ell \]
  done clear
  B)
  \[2\ell \]
  done clear
  C)
  \[\ell /2\]
  done clear
  D)
  \[\ell /4\]
  done clear
  View Answer play_arrow

• question_answer60) The supply voltage to a room is 120 V. The resistance of the lead wires is\[6\Omega .\] A 60 W bulb is already switched on. What is the decrease of voltage across the bulb, when a 240 W heater is switched on in parallel to the bulb?       [JEE MAIN 2013]
  A)
  zero Volt
  done clear
  B)
  2.9 Volt
  done clear
  C)
  13.3 Volt
  done clear
  D)
  None of these
  done clear
  View Answer play_arrow

• question_answer61) 

  This question has statement I and Statement II. Of the four choices given after the Statements choose the one that best describes the two statements.

  Statement − I: Higher the range greater is the resistance of ammeter.

  Statement − II: To increase the range of ammeter additional shunt needs to be used across it    [JEE MAIN 2013]

  A)
  Statement - I is true, Statements - II is true, Statement - II is the correct explanation of Statements - I
  done clear
  B)
  Statement - I is true, Statement - II is true, Statement - II is not the correct explanation of Statement - I.
  done clear
  C)
  Statement - I is true, Statement - II is false.
  done clear
  D)
  Statement - I is false, Statement - II is true.
  done clear
  View Answer play_arrow

• question_answer62) In a metre bridge experiment null point is obtained at 40 cm from end of the wire when resistance X is balanced against another resistance Y. if X < Y, then the new position of the null point from the same end, if one decides to balance a resistance of  3X  against Y, will be close to:             [JEE ONLINE 09-04-2013]
  A)
  80 cm
  done clear
  B)
  75 cm 
  done clear
  C)
  67 cm
  done clear
  D)
  50 cm
  done clear
  View Answer play_arrow

• question_answer63) A letter ‘A’ is constructed of a uniform wire with resistance 1.0 \[\Omega \] per cm. The sides of the letter are 20 cm and the cross piece in the middle is 10 cm long. The apex angle is \[{{60}^{0}}\]. The resistance between the ends of the legs is close to: [JEE ONLINE 09-04-2013]
  A)
              \[50.0\Omega \]
  done clear
  B)
  \[10\Omega \]
  done clear
  C)
              \[36.7\Omega \]
  done clear
  D)
  \[26.7\Omega \]
  done clear
  View Answer play_arrow

• question_answer64) A shunt of resistance 1\[\Omega \] connected across a galvanometer of 120\[\Omega \]resistance. A current of 5.5 ampere gives full scale deflection in the galvanometer. The current that will give full scale deflection in the absence of the shunt is nearly:                   [JEE ONLINE 09-04-2013]
  A)
  5.5 ampere
  done clear
  B)
  0.5 ampere
  done clear
  C)
              0.004 ampere
  done clear
  D)
  0.045 ampere
  done clear
  View Answer play_arrow

• question_answer65) 

  A dc source of emf \[{{E}_{1}}=100\,V\] and internal resistance \[\operatorname{r}=0.5\Omega ,\] a storage battery of emf \[{{\operatorname{E}}_{2}}=90\operatorname{V}\] and an external resistance R are connected as shown in figure. For what value of R no current will pass through the battery? [JEE ONLINE 22-04-2013]

  A)
              \[5.5\,\,\Omega \]
  done clear
  B)
  \[3.5\,\,\Omega \]
  done clear
  C)
              \[4.5\,\,\Omega \]
  done clear
  D)
  \[2.5\,\,\Omega \]
  done clear
  View Answer play_arrow

• question_answer66) 

  To find the resistance of galvanometer by the half deflection method the following circuit is used with resistances \[{{\operatorname{R}}_{1}}=9970\Omega ,{{\operatorname{R}}_{2}}=30\Omega \] and \[{{\operatorname{R}}_{3}}=0\]. The deflection in the galvanometer is d. With \[{{\operatorname{R}}_{3}}=107\Omega \]the deflection changed to \[\frac{\operatorname{d}}{2}.\] The galvanometer resistance is approximately:         [JEE ONLINE 22-04-2013]

  A)
              \[107\Omega \]
  done clear
  B)
  \[137\Omega \]
  done clear
  C)
              \[107/2\Omega \]
  done clear
  D)
  \[77\,\Omega \]
  done clear
  View Answer play_arrow

• question_answer67) Correct set up to verify Ohm’s law is:                                [JEE ONLINE 23-04-2013]
  A)
             
  done clear
  B)
             
  done clear
  C)
             
  done clear
  D)
  
  done clear
  View Answer play_arrow

• question_answer68) 

  Which of the four resistances P, Q, R and S generate the greatest amount of heat when a current flows from A to B?                                           [JEE ONLINE 23-04-2013]

  A)
              Q
  done clear
  B)
  S
  done clear
  C)
              P
  done clear
  D)
  R
  done clear
  View Answer play_arrow

• question_answer69) 

  Six equal resistances are connected between points P, Q and R a shown in figure. The net resistance will be maximum between:              [JEE ONLINE 25-04-2013]

  A)
  P and R
  done clear
  B)
  P and Q
  done clear
  C)
  Q and R
  done clear
  D)
  any two points
  done clear
  View Answer play_arrow

• question_answer70) In a large building, there are 15 bulbs of 40 W, 5 bulbs of 100 W, 5 fans of 80 W and 1 heater of 1 kW. The voltage of the electric mains is 220 V. The minimum capacity of the main fuse of the building will be:                          [JEE MAIN 2014]
  A)
  12 A
  done clear
  B)
  14 A
  done clear
  C)
  8 A
  done clear
  D)
  10 A
  done clear
  View Answer play_arrow

• question_answer71) 

  A d.c. main supply of e.m.f. 220 V is connected across a storage battery of e.m.f. 200 V through a resistance of \[1\Omega .\]

  The battery terminals are connected to an external resistance ‘R’. The minimum value of ‘R’, so that a current passes through the battery to charge it is: [JEE ONLINE 09-04-2014]

  A)
  \[7\Omega \]
  done clear
  B)
  \[9\Omega \]
  done clear
  C)
  \[11\Omega \]
  done clear
  D)
  Zero
  done clear
  View Answer play_arrow

• question_answer72) 

  In the circuit shown, current (in A) through 50 V and 30 V batteries are, respectively:

  [JEE ONLINE 11-04-2014]

  A)
  2.5 and 3
  done clear
  B)
  3.5 and 2
  done clear
  C)
  4.5 and 1
  done clear
  D)
  None of these
  done clear
  View Answer play_arrow

• question_answer73) 

  In the circuit diagrams (A, B, C and D) shown below, R is a high resistance and S is a resistance of the order of galvanometer resistance G. The correct circuit, corresponding to the half deflection method for finding the resistance and figure of merit of the galvanometer, is the circuit labelled as: [JEE ONLINE 11-04-2014]

  [a]

  [b]

  [c]

  [d]

  A)
  Circuit A with G\[\frac{RS}{(R-S)}\]
  done clear
  B)
  Circuit B with G = S
  done clear
  C)
  Circuit C with G = S
  done clear
  D)
  Circuit D with G = \[\frac{RS}{(R-S)}\]
  done clear
  View Answer play_arrow

• question_answer74) 

  The circuit shown here has two batteries of 8.0 V and 16.0 V and three resistors \[3\Omega ,9\Omega \]and \[9\Omega \] and a capacitor of 5.0 \[\mu F.\]

  How much is the current I in the circuit in steady state?                    [JEE ONLINE 12-04-2014]

  A)
  1.6 A
  done clear
  B)
  0.67 A
  done clear
  C)
  2.5 A
  done clear
  D)
  0.25 A
  done clear
  View Answer play_arrow

• question_answer75) 

  In the experiment of calibration of voltmeter, a standard cell of e.m.f. 1.1 volt is balanced against 440 cm of potential wire.

  The potential difference across the ends of resistance is found to balance against 220 cm of the wire. The corresponding reading of voltmeter is 0.5 volt. The error in the reading of volmeter will be: [JEE ONLINE 12-04-2014]

  A)
  0. 15 volt
  done clear
  B)
  0.15 volt
  done clear
  C)
  0.5 volt
  done clear
  D)
  - 0.05 volt
  done clear
  View Answer play_arrow

• question_answer76) 

  Four bulbs B1, B2, B3 and B4 of 100 W each are connected to 220 V main as shown in the figure. [JEE ONLINE 19-04-2014]

  The reading in an ideal ammeter will be:

  A)
  0.45 A
  done clear
  B)
  0.90 A
  done clear
  C)
  1.35 A
  done clear
  D)
  1.80 A
  done clear
  View Answer play_arrow

• question_answer77) When 5V potential difference is applied across a wire of length 0.1 m, the drift speed of electrons \[2.5\times {{10}^{-4}}m{{s}^{-1}}.\]If the electron density in the wire is \[8\times {{10}^{28}}{{m}^{-3}},\]the resistivity of the material is close to [JEE MAIN 2015]
  A)
  \[1.6\times {{10}^{-6}}\Omega m\]
  done clear
  B)
  \[1.6\times {{10}^{-5}}\Omega m\]
  done clear
  C)
  \[1.6\times {{10}^{-8}}\Omega m\]
  done clear
  D)
  \[1.6\times {{10}^{-7}}\Omega m\]
  done clear
  View Answer play_arrow

• question_answer78) 

  In the circuit shown, the current in the \[1\Omega \] resistor is:                           [JEE MAIN 2015]

  A)
  0.13 A, from Q to P       
  done clear
  B)
  0.13 A, from P to Q
  done clear
  C)
  1.3 A, from P to Q
  done clear
  D)
  0A55
  done clear
  View Answer play_arrow

• question_answer79) Suppose the drift velocity Vi in a material varied with the applied electric field E as \[{{\upsilon }_{d}}\propto \sqrt{E}.\]Then V - I graph for a wire made of such a material is best given by:                                                      [JEE ONLINE 10-04-2015]
  A)
            
  done clear
  B)
  
  done clear
  C)
  
  done clear
  D)
  
  done clear
  View Answer play_arrow

• question_answer80) de-Broglie wavelength of an electron accelerated by a voltage of 50 V is close to [JEE ONLINE 10-04-2015] \[(|e|=1.6\times {{10}^{-19}}C,{{m}_{e}}=9.1\times {{10}^{-31}}kg,h=6.6\times {{10}^{-34}}Js)\]
  A)
  \[0.5{\AA}\]
  done clear
  B)
  \[1.7{\AA}\]
  done clear
  C)
  \[2.4{\AA}\]      
  done clear
  D)
  \[1.2{\AA}\]
  done clear
  View Answer play_arrow

• question_answer81) 

  A 10V battery with internal resistance \[1\Omega \]and a 15 V battery with internal resistance \[0.6\Omega \] are connected in parallel to a voltmeter (see figure). The reading in the voltmeter will be close to: [JEE ONLINE 10-04-2015]

  A)
  11.9 V
  done clear
  B)
  13.1 V
  done clear
  C)
  12.5 V
  done clear
  D)
  24.5 V
  done clear
  View Answer play_arrow

• question_answer82) 

  In the electric network shown, when no current flows through the \[4\Omega \]resistor in the arm EB, the potential difference between the points A and D will be :                           [JEE MAIN 11-04-2015]

  A)
  3V
  done clear
  B)
  4V
  done clear
  C)
  5V
  done clear
  D)
  6V
  done clear
  View Answer play_arrow

• question_answer83) A galvanometer having a coil resistance of \[100\Omega \] gives a full scale deflection, when a current of 1 mA is passed through it. The value of the resistance, which can convert this galvanometer into ammeter giving a full scale deflection for a current of 10A, is :- [JEE MAIN - I 3-4-2016]
  A)
  \[3\Omega \]
  done clear
  B)
  \[0.01\Omega \]
  done clear
  C)
  \[2\Omega \]
  done clear
  D)
  \[0.1\Omega \]
  done clear
  View Answer play_arrow

• question_answer84) The temperature dependence of resistances of Cu and un doped Si in the temperature range 300-400K, is best described by :-            [JEE MAIN - I 3-4-2016]
  A)
  Linear decrease for Cu, linear decrease for Si.
  done clear
  B)
  Linear increase for Cu, linear increase for Si.
  done clear
  C)
  Linear increase for Cu, exponential increase for Si
  done clear
  D)
  Linear increase for Cu, exponential de crease for Si
  done clear
  View Answer play_arrow

• question_answer85) To know the resistance G of a galvanometer by half deflection method, a battery of emf \[{{V}_{E}}\] and resistance R is used to deflect the galvanometer by angle\[\theta .\]If a shunt of resistance S is needed to gat half deflection then G, R and S are related by the equation:   [JEE ONLINE 09-04-2016]
  A)
  2S = G
  done clear
  B)
  2G = S
  done clear
  C)
  S(R+G) = RG
  done clear
  D)
  2S(R+G) = RG
  done clear
  View Answer play_arrow

• question_answer86) 

  In the circuit shown, the resistance r is a variable resistance. If for \[r=fR,\] the heat generation in r is maximum then the value of f is:               [JEE ONLINE 09-04-2016]

  A)
  1
  done clear
  B)
  \[\frac{3}{4}\]
  done clear
  C)
  \[\frac{1}{4}\]
  done clear
  D)
  \[\frac{1}{2}\]
  done clear
  View Answer play_arrow

• question_answer87) \[A50\Omega \]resistance is connected to a battery of 5V. A galvanometer of resistance \[100\Omega \]is to be used as ammeter to measure current through the resistance, for this a resistance \[{{r}_{s}}\] is connected to the galvanometer. Which of the following connections should be employed if the measured current is within 1% of the current without the ammeter in the circuit?                                 [JEE ONLINE 09-04-2016]
  A)
  \[{{r}_{s}}=0.5\Omega n\]parallel with the galvanometer
  done clear
  B)
  \[{{r}_{s}}=0.5\Omega \]in series with the galvanometer
  done clear
  C)
  \[{{r}_{s}}=1\Omega \] in series with galvanometer
  done clear
  D)
  \[{{r}_{s}}=1\Omega \] in parallel with galvanometer
  done clear
  View Answer play_arrow

• question_answer88) 

  A galvanometer has a 50 division scale. Battery has no internal resistance. It is found that there is deflection of 40 divisions when \[R=2400\,\,\Omega \].Deflection becomes 20 divisions when resistance taken form resistance box is\[4900\,\,\,\Omega \]. Then we can conclude:            [JEE ONLINE 10-04-2016]

  A)
  Resistance required on R.B. For a deflection of 10 divisions is \[9800\,\,\,\Omega \].
  done clear
  B)
  Full scale deflection current is 2 mA.
  done clear
  C)
  Current sensitivity of galvanometer is \[20\mu A/\] division.
  done clear
  D)
  None of these
  done clear
  View Answer play_arrow

• question_answer89) A particle of mass M is moving in a circle of fixed radius R in such a way that its centripetal acceleration at time t is given by \[{{n}^{2}}R\,{{t}^{2}}\] where n is a constant. The power delivered to the particle by the force acting on it, is:[JEE ONLINE 10-04-2016]
  A)
  \[M\,\,n\,{{R}^{2}}\,{{t}^{2}}\]
  done clear
  B)
  \[\frac{1}{2}M{{n}^{2}}{{R}^{2}}{{t}^{2}}\]
  done clear
  C)
  \[M\,{{n}^{2}}{{R}^{2}}t\]
  done clear
  D)
  \[M\,n\,{{R}^{2}}\,t\]
  done clear
  View Answer play_arrow

• question_answer90) The resistance of an electrical toaster has a temperature dependence given by \[R\,\,(T)={{R}_{0}}[1+\alpha (T-{{T}_{0}}]\] in its range of operation. At \[{{T}_{0}}=300\,K,\,R=100\Omega \]. And at\[T=500\,K,\,R=120\Omega \]. The toaster is connected to a voltage source at 200 V and its temperature is raised at a constant rate from 300 to 500 K in 30s. The total work done in raising the temperature is: [JEE ONLINE 10-04-2016]
  A)
              \[400\,In\frac{1.5}{1.3}J\]
  done clear
  B)
              300 J
  done clear
  C)
  \[200\,In\frac{2}{3}J\]
  done clear
  D)
  \[400\,In\frac{5}{6}J\]
  done clear
  View Answer play_arrow

• question_answer91) Which of the following statements is false?    [JEE Main 2017]
  A)
  A rheostat can be used as a potential divider
  done clear
  B)
  Kirchhoff's second law represents energy conservation
  done clear
  C)
  Wheatstone bridge is the most sensitive when all the four resistances are of the same order of magnitude.
  done clear
  D)
  In a balanced wheat stone bridge if the cell and the galvanometer are exchanged, the null point is disturbed.
  done clear
  View Answer play_arrow

• question_answer92) When a current of 5 mA is passed through a galvanometer having a coil of resistance \[15\,\Omega ,\] it shows full scale deflection. The value of the resistance to be put in series with the galvanometer to convert it into to voltmeter of range 0 - 10 V is:          [JEE Main 2017]
  A)
  \[2.535\times {{10}^{3}}\Omega \]
  done clear
  B)
  \[4.005\times {{10}^{3}}\Omega \]
  done clear
  C)
  \[1.985\times {{10}^{3}}\Omega \]
  done clear
  D)
  \[2.045\times {{10}^{3}}\Omega \]
  done clear
  View Answer play_arrow

• question_answer93) 

  In the above circuit the current in each resistance is:                               [JEE Main 2017]

  A)
  0.5
  done clear
  B)
  0 A
  done clear
  C)
  1 A
  done clear
  D)
  0.25 A
  done clear
  View Answer play_arrow

• question_answer94) 

  In the given circuit diagram when the current reaches steady state in the circuit, the charge on the capacitor of capacitance C will be: [JEE Main 2017]

  A)
  \[CE\frac{{{r}_{2}}}{(r+{{r}_{2}})}\]
  done clear
  B)
  \[CE\frac{{{r}_{1}}}{({{r}_{1}}+r)}\]
  done clear
  C)
  CE
  done clear
  D)
  \[CE\frac{{{r}_{1}}}{({{r}_{2}}+r)}\]
  done clear
  View Answer play_arrow

• question_answer95) 

  A potentiometer PQ is set up to comapre two resistances as shown in the figure. The ammeter A in the circuit reads 1.0 A when two way key \[{{K}_{3}}\] is open. The balance point is at a length \[{{l}_{1}}\]cm from P when two way key \[{{K}_{3}}\] is plugged in between 2 and 1, while the balance point is at a length \[{{l}_{2}}\] cm from P when key \[{{K}_{3}}\] is plugged in between 3 and 1. The ratio of the two resistance \[\frac{{{R}_{1}}}{{{R}_{2}}},\] is found to be -  [JEE Online 08-04-2017]

  A)
  \[\frac{{{l}_{1}}}{{{l}_{1}}-{{l}_{2}}}\]
  done clear
  B)
  \[\frac{{{l}_{2}}}{{{l}_{2}}-{{l}_{1}}}\]
  done clear
  C)
  \[\frac{{{l}_{1}}}{{{l}_{1}}+{{l}_{2}}}\]
  done clear
  D)
  \[\frac{{{l}_{1}}}{{{l}_{2}}-{{l}_{1}}}\]
  done clear
  View Answer play_arrow

• question_answer96) 

  A 9 V battery with internal resistance of \[0.5\Omega \] is connected across an infinite network as shown in the figure. All ammeters A1, A2, A3 and voltmeter V are ideal.

  Choose correct statement. [JEE Online 08-04-2017]

  A)
  Reading of \[{{A}_{1}}\] is 18 A
  done clear
  B)
  Reading of V is 9 V
  done clear
  C)
  Reading of V is 7 V
  done clear
  D)
  Reading of \[{{A}_{1}}\] is 2 A
  done clear
  View Answer play_arrow

• question_answer97) 

  In a meter bridge experiment resistances are connected as shown in the figure. Initially resistance \[P=4\,\Omega \] and the neutral point N is at 60 cm from A. Now an unknown resistance R is connected in series to P and the new position of the neutral point is at 80 cm from A. The value of unknown resistance R is - [JEE Online 09-04-2017]

  A)
  \[\frac{33}{5}\Omega \]
  done clear
  B)
  \[5\,\Omega \]
  done clear
  C)
  \[\frac{20}{3}\Omega \]
  done clear
  D)
  \[7\,\,\Omega \]
  done clear
  View Answer play_arrow

• question_answer98) A uniform wire of length I and radius r has a resistance of \[100\,\Omega \]. It is recast into a wire of radius \[\frac{r}{2}\]. The resistance of new wire will be - [JEE Online 09-04-2017]
  A)
  \[1600\,\Omega \]
  done clear
  B)
  \[100\,\Omega \]
  done clear
  C)
  \[200\,\Omega \]
  done clear
  D)
  \[400\,\Omega \]
  done clear
  View Answer play_arrow

• question_answer99) 

  The figure shows three circuits I, II and III which are connected to a 3V battery. If the powers dissipated by the configurations I, II and III are \[{{P}_{1}},{{P}_{2}}\] and \[{{P}_{3}}\] respectively, then - [JEE Online 09-04-2017]

  A)
  \[{{P}_{2}}>{{P}_{1}}>{{P}_{3}}\]
  done clear
  B)
  \[{{P}_{1}}>{{P}_{2}}>{{P}_{3}}\]
  done clear
  C)
  \[{{P}_{3}}>{{P}_{2}}>{{P}_{1}}\]
  done clear
  D)
  \[{{P}_{1}}>{{P}_{3}}>{{P}_{2}}\]
  done clear
  View Answer play_arrow

• question_answer100) Two batteries with e.m.f. 12 V and 13 V are connected in parallel across a load resistor of\[10\,\,\Omega \]. The internal resistances of the two batteries are \[1\,\,\Omega \]and \[2\,\,\Omega \] respectively. The voltage across the load lies between: [JEE Main Online 08-04-2018]
  A)
  \[\text{11}\text{.4 V and 11}\text{.5 V}\]
  done clear
  B)
  \[\text{11}\text{.7 V and 11}\text{.8 V}\]
  done clear
  C)
  \[\text{11}\text{.6 V and 11}\text{.7 V}\]
  done clear
  D)
  \[\text{11}\text{.5 V and 11}\text{.6 V}\]
  done clear
  View Answer play_arrow

• question_answer101) In a potentiometer experiment, it is found that no current passes that no current passes through the galvanometer when the terminals of the cell are connected across 52 cm of the potentiometer wire. If the cell is shunted by a resistance of \[\text{5 }\Omega \], a balance is found when the cell is connected across 40 cm of the wire. Find the internal resistance of the cell.   [JEE Main Online 08-04-2018]
  A)
  \[2\,\Omega \]
  done clear
  B)
  \[\text{2}\text{.5 }\Omega \]
  done clear
  C)
  \[\text{1 }\Omega \]
  done clear
  D)
  \[\text{1}\text{.5 }\Omega \]
  done clear
  View Answer play_arrow

• question_answer102) On interchanging the resistances, the balance point of a meter bridge shifts to the left by 10 cm. The resistance of their series combination is\[\text{1 k}\Omega \]. How much was the resistance on the left slot before interchanging the resistances? [JEE Main Online 08-04-2018]
  A)
  \[\text{550 }\Omega \]
  done clear
  B)
  \[\text{910 }\Omega \]
  done clear
  C)
  \[\text{990 }\Omega \]
  done clear
  D)
  \[\text{505 }\Omega \]
  done clear
  View Answer play_arrow

• question_answer103) 

  In the given circuit all resistances are of value \[R\] ohm each. The equivalent resistance between \[A\] and \[B\] is:          [JEE Online 15-04-2018]

  A)
  \[2R\]
  done clear
  B)
  \[\frac{5R}{2}\]
  done clear
  C)
  \[\frac{5R}{3}\]
  done clear
  D)
  \[3R\]
  done clear
  View Answer play_arrow

• question_answer104) 

  In a meter bridge, as shown in the figure, it is given that resistance \[Y=12.5\Omega \] and that the balance is obtained at a distance \[39.5cm\] from end \[A\] (by jockey J). After interchanging the resistances \[X\] and\[Y\], a new balance point is found at a distance \[{{l}_{2}}\] from end \[A\]. What are the values of \[X\]and \[{{l}_{2}}\]? [JEE Online 15-04-2018]

  A)
  \[\text{19}\text{.15 }\Omega \] and \[\text{39}\text{.5 cm}\]
  done clear
  B)
  \[\text{8}\text{.16 }\Omega \text{ and 60}\text{.5 cm}\]
  done clear
  C)
  \[\text{19}\text{.15}\,\,\text{ }\!\!\Omega\!\!\text{ }\,\,\text{and}\,\,\text{60}\text{.5}\,\,\text{cm}\]
  done clear
  D)
  \[\text{8}\text{.16}\,\,\Omega \text{ and 39}\text{.5 cm}\]
  done clear
  View Answer play_arrow

• question_answer105) A constant voltage is applied between two ends of a metallic wire. If the length is halved and the radius of the wire is doubled, the rate of heat developed in the wire will be: [JEE Online 15-04-2018 (II)]
  A)
  Increased 8 times
  done clear
  B)
  Doubled
  done clear
  C)
  Halved
  done clear
  D)
  Unchanged
  done clear
  View Answer play_arrow

• question_answer106) A copper rod of cross-sectional area \[A\] carries a uniform current \[I\] through if. At temperature \[T\], if the volume charge density of the rod is \[\rho \], how long will the charges take to travel a distance \[d\]? [JEE Online 15-04-2018 (II)]
  A)
  \[\frac{2\rho dA}{IT}\]
  done clear
  B)
  \[\frac{2\rho dA}{I}\]
  done clear
  C)
  \[\frac{\rho dA}{I}\]
  done clear
  D)
  \[\frac{\rho dA}{IT}\]
  done clear
  View Answer play_arrow

• question_answer107) A heating element has a resistance of \[100\Omega \]at room temperature. When it is connected to a supply of 220V, a steady current of 2A passes in it and temperature is\[500{{\,}^{o}}C\]more than room temperature. What is the temperature coefficient of resistance of the heating element?              [JEE Main Online 16-4-2018]
  A)
  \[1\times {{10}^{-4}}{{\,}^{o}}{{C}^{-1}}\]
  done clear
  B)
  \[5\times {{10}^{-4}}{{\,}^{o}}{{C}^{-1}}\]
  done clear
  C)
  \[2\times {{10}^{-4}}{{\,}^{o}}{{C}^{-1}}\]
  done clear
  D)
  \[0.5\times {{10}^{-4}}{{\,}^{o}}{{C}^{-1}}\]
  done clear
  View Answer play_arrow

• question_answer108) In a circuit for finding the resistance of a galvanometer by half deflection method, a 6V battery and a high resistance of\[11\,k\Omega \] are used. The figure of merit of the galvanometer \[60\mu A/division.\]In the absence of shunt resistance, the galvanometer produces a deflection of\[\theta =9\]divisions when current flows in the circuit. The value of the shunt resistance that can cause the deflection of \[\theta /2,\] is closest to [JEE Main Online 16-4-2018]
  A)
  \[55\Omega \]
  done clear
  B)
  \[110\Omega \]
  done clear
  C)
  \[220\Omega \]
  done clear
  D)
  \[550\Omega \]
  done clear
  View Answer play_arrow

• question_answer109) 

  In the following circuit, the switch S is closed at\[t=0.\]The charge on the capacitor\[{{C}_{1}}\]as a function of time will be given by \[\left( {{C}_{eq}}=\frac{{{C}_{1}}{{C}_{2}}}{{{C}_{1}}+{{C}_{2}}} \right).\] [JEE Main Online 16-4-2018]

  A)
              \[{{C}_{eq}}E[1-\exp (-t/R{{C}_{eq}})]\]           
  done clear
  B)
  \[{{C}_{1}}E[1-\exp (-tR/{{C}_{1}})]\]
  done clear
  C)
              \[{{C}_{2}}E[1-\exp (-t/R{{C}_{2}})]\] 
  done clear
  D)
  \[{{C}_{eq}}E\exp (-t/R{{C}_{eq}})\] 
  done clear
  View Answer play_arrow

• question_answer110) A galvanometer with its coil resistance \[25\Omega \]requires a current of 1mA for its full deflection. In order to construct an ammeter to read up to a current of 2A, the approximate value of the shunt resistance should be [JEE Main Online 16-4-2018]
  A)
  \[2.5\times {{10}^{-2}}\Omega \]
  done clear
  B)
  \[1.25\times {{10}^{-3}}\Omega \]
  done clear
  C)
  \[2.5\times {{10}^{-3}}\Omega \]
  done clear
  D)
  \[1.25\times {{10}^{-2}}\Omega \]  
  done clear
  View Answer play_arrow

• question_answer111) Drift speed of electrons, when \[1.5\text{ }A\] of current flows in a copper wire of cross section \[5\text{ }m{{m}^{2}}\], is v. If electron density in copper is \[9\times {{10}^{28}}/{{m}^{3}}\] the value of v in mm/s is close to (Take charge of electron to be \[=\text{ }1.6\times {{10}^{-19}}C)\] [JEE Main 09-Jan-2019 Morning]
  A)
              0.02
  done clear
  B)
  0.2
  done clear
  C)
              3
  done clear
  D)
  2
  done clear
  View Answer play_arrow

• question_answer112) 

  An infinitely long current carrying wire and a small current carrying loop are in the plane of the paper as shown. The radius of the loop is a and distance of its centre from the wire is \[d\left( d>>a \right)\]. If the loop applies a force F on the wire then: [JEE Main 09-Jan-2019 Morning]

  A)
              \[F\propto \left( \frac{{{a}^{2}}}{{{d}^{3}}} \right)\]
  done clear
  B)
  \[F\propto \left( \frac{a}{d} \right)\]
  done clear
  C)
              \[F\,\,=\,\,0\]
  done clear
  D)
  \[F\propto {{\left( \frac{a}{d} \right)}^{2}}\]
  done clear
  View Answer play_arrow

• question_answer113) 

  When the switch S, in circuit shown, is closed, then the value of current i will be: [JEE Main 09-Jan-2019 Morning]

  A)
  4 A
  done clear
  B)
  5 A   
  done clear
  C)
  3 A
  done clear
  D)
  2 A
  done clear
  View Answer play_arrow

• question_answer114) A conducting circular loop made of a thin wire, has area \[3.5\,\,\times \,\,{{10}^{-3}}\,{{m}^{2}}\] and resistance 100. It is placed perpendicular to a time dependent magnetic field \[B\left( t \right)=\left( 0.4T \right)sin\left( 50\pi t \right)\]. The field is uniform in space. Then the net charge flowing through the loop during \[t\,\,=\,\,0\] s and \[t\,\,=\,\,0\] ms is close to:[JEE Main 09-Jan-2019 Morning]
  A)
              6 m C
  done clear
  B)
  14 m C
  done clear
  C)
              7 m C
  done clear
  D)
  None of these
  done clear
  View Answer play_arrow

• question_answer115) A copper wire is stretcher! to make it \[0.5\,%\] longer. The percentage change m in its electrical resistance if its volume remain unchanged is: [JEE Main 09-Jan-2019 Morning]
  A)
  \[0.5\text{ }%\]
  done clear
  B)
  \[2.5\text{ }%\]
  done clear
  C)
  \[2.0\text{ }%\]
  done clear
  D)
  \[1.0\text{ }%\]
  done clear
  View Answer play_arrow

• question_answer116) 

  A resistance is shown in the figure. Its value and tolerance are given respectively by: [JEE Main 09-Jan-2019 Morning]

  A)
              \[270\text{ }\Omega ,\text{ }10\text{ }%\]
  done clear
  B)
  \[270\text{ }\Omega ,\text{ }5\text{ }%\]
  done clear
  C)
              \[27\text{ }k\Omega ,\text{ }10\,%\]
  done clear
  D)
  \[27\text{ }k\Omega ,\text{ }20\,%\]
  done clear
  View Answer play_arrow

• question_answer117) 

  A carbon resistance has a following colour code. What is the value of the resistance? [JEE Main 09-Jan-2019 Evening]

  A)
  \[5.3\,M\,\Omega \,\,\pm \,\,5\,%\]
  done clear
  B)
  \[530\,k\,\Omega \,\,\pm \,\,5%\]
  done clear
  C)
  \[6.4\,k\,\Omega \,\,\pm \,10%\]
  done clear
  D)
  \[6.4\,M\Omega \,\,\pm \,\,5%\]
  done clear
  View Answer play_arrow

• question_answer118) A uniform metallic wire has a resistance of \[18\,\Omega \] and is bent into an equilateral triangle. Then, the resistance between any two vertices of the triangle is- [JEE Main 10-Jan-2019 Morning]
  A)
  \[12\,\Omega \]
  done clear
  B)
  \[2\,\Omega \]
  done clear
  C)
  \[4\,\Omega \]
  done clear
  D)
  \[8\,\Omega \]
  done clear
  View Answer play_arrow

• question_answer119) A 2 W carbon resistor is color coded with green, black, red and brown respectively. The maximum current which can be passed through this resistor is-                                                     [JEE Main 10-Jan-2019 Morning]
  A)
  0.4 mA
  done clear
  B)
  20 mA
  done clear
  C)
  63 mA
  done clear
  D)
  100 mA
  done clear
  View Answer play_arrow

• question_answer120) 

  In the given circuit the cells have zero internal resistance. The currents (in Amperes) passing through resistance \[{{R}_{1}}and\text{ }{{R}_{2}}\] respectively, are [JEE Main 10-Jan-2019 Morning]

  A)
  0.5, 0
  done clear
  B)
  0, 1   
  done clear
  C)
  1, 2
  done clear
  D)
  2, 2
  done clear
  View Answer play_arrow

• question_answer121) 

  A potentiometer wire AB having length L and resistance 12 r is joined to a cell D of emf \[\varepsilon \] and internal resistance r. A cell C having emf \[\varepsilon /2\] and internal resistance 3r is connected. The length AJ at which the galvanometer as shown in figure shows no deflection is-       [JEE Main 10-Jan-2019 Morning]

  A)
        \[\frac{11}{12}\,L\]
  done clear
  B)
  \[\frac{13}{24}\,L\]
  done clear
  C)
  \[\frac{5}{12}\,L\]
  done clear
  D)
  \[\frac{11}{24}\,L\]
  done clear
  View Answer play_arrow

• question_answer122) 

  The Wheatstone bridge shown in figure, here, gets balanced when the carbon resistor used as \[{{R}_{1}}\] has the colour code (Orange, Red, Brown).  he resistors R2 and R4 are 800. and 400, respectively. Assuming that the colour code for the carbon resistors gives their accurate values, the colour code for the carbon resistor, used as Rs, would be-

  [JEE Main 10-Jan-2019 Evening]

  A)
  Brown, Blue, Brown
  done clear
  B)
  Grey, Black, Brown
  done clear
  C)
  Red, Green, Brown
  done clear
  D)
  Brown, Blue, Black
  done clear
  View Answer play_arrow

• question_answer123) 

  The actual value of resistance R, shown in the figure is \[30\,\Omega \]. This is measured in an experiment as shown using the standard formula \[R=\frac{V}{I}\] where V and I are the readings of the voltmeter and ammeter, respectively. If the measured value of R is \[5%\] less, then the internal resistance of the voltmeter is- [JEE Main 10-Jan-2019 Evening]

  A)
  570 \[\Omega \]
  done clear
  B)
  600 \[\Omega \]
  done clear
  C)
  350 \[\Omega \]
  done clear
  D)
  35 \[\Omega \]
  done clear
  View Answer play_arrow

• question_answer124) Two equal resistances when connected in series to a battery, consume electric power of 60 W. If these resistances are now connected in parallel combination to the same battery, the electric power consumed will be- [JEE Main 11-Jan-2019 Morning]
  A)
  240 W
  done clear
  B)
  120 W
  done clear
  C)
  60 W
  done clear
  D)
  30 W
  done clear
  View Answer play_arrow

• question_answer125) 

  The resistance of the meter bridge AB in given figure is \[4\Omega .\] With a cell of emf \[\varepsilon =0.5V\]and rheostat resistance \[{{R}_{h}}=2\Omega \]the null point is obtained at some point J. When the cell is replaced by another one of emf \[\varepsilon ={{\varepsilon }_{2}}\]the same null point J is found for\[{{R}_{h}}=6\Omega .\]                          [JEE Main 11-Jan-2019 Morning]

  The emf \[{{\varepsilon }_{2}}\] is

  A)
  0.5 V
  done clear
  B)
  0.4 V
  done clear
  C)
  0.5 V
  done clear
  D)
  0.3 V
  done clear
  View Answer play_arrow

• question_answer126) 

  In the figure shown below, the charge on the left plate of the \[10\mu F\]capacitor is \[-30\,\mu C\]. The charge on the right plate of the \[6\,\mu F\]capacitor is-             [JEE Main 11-Jan-2019 Morning]

  A)
  \[-18\,\mu C\]
  done clear
  B)
  \[-12\,\mu C\]
  done clear
  C)
  \[+12\,\mu C\]
  done clear
  D)
  \[+18\,\mu C\]
  done clear
  View Answer play_arrow

• question_answer127) 

  In a Wheatstone bridge (see fig), Resistances P and Q are approximately equal. When \[R=400\Omega ,\]the bridge is balanced. On interchanging P and Q, the value of R, for balance, is \[405\Omega ,\]The value of X is  close to-

  [JEE Main 11-Jan-2019 Morning]

  A)
  401.5 ohm
  done clear
  B)
  404.5 ohm
  done clear
  C)
  403.5 ohm
  done clear
  D)
  402.5 ohm
  done clear
  View Answer play_arrow

• question_answer128) 

  In the circuit shown,                                            [JEE Main 11-Jan-2019 Morning]

  the switch \[{{S}_{1}}\] is closed at time t = 0 and the  switch\[{{S}_{1}}\]is opened and \[{{S}_{2}}\] is closed. The behavior of the current I as a function of time ‘t’ is given by

  A)
  
  done clear
  B)
  
  done clear
  C)
  
  done clear
  D)
  
  done clear
  View Answer play_arrow

• question_answer129) 

  In the given circuit the current through Zener Diode is close to- [JEE Main 11-Jan-2019 Morning]

  A)
  4.0 mA
  done clear
  B)
  0.0 mA
  done clear
  C)
  6.0 mA
  done clear
  D)
  6.7 mA
  done clear
  View Answer play_arrow

• question_answer130) A liquid of density \[\rho \] is coming out of a hose pipe of radius a with horizontal speed v and hits a mesh. 50% of the liquid passes through the mesh unaffected. 25% looses all of its momentum and 25% comes back with the same speed. The resultant pressure on the mesh will be-           [JEE Main 11-Jan-2019 Morning]
  A)
  \[\rho {{v}^{2}}\]
  done clear
  B)
  \[\frac{1}{4}\rho {{v}^{2}}\]
  done clear
  C)
  \[\frac{3}{4}\rho {{v}^{2}}\]
  done clear
  D)
  \[\frac{1}{2}\rho {{v}^{2}}\]
  done clear
  View Answer play_arrow

• question_answer131) 

  In the circuit shown, the potential difference between A and B is- [JEE Main 11-Jan-2019 Evening]

  A)
  6V
  done clear
  B)
  3 V 
  done clear
  C)
  2 V
  done clear
  D)
  1 V
  done clear
  View Answer play_arrow

• question_answer132) 

  In the experimental set up of metre bridgre shown in the figure, the null point is obtained at a distance of 40 cm from A. If a \[10\Omega \]resistor is connected in series with \[{{R}_{1}},\] the null point shifts by 10 cm. The resistance that should be connected in parallel with \[({{R}_{1}}+10)\Omega \] such that the null point shifts back to its initial position is- [JEE Main 11-Jan-2019 Evening]

  A)
  \[40\,\Omega \]
  done clear
  B)
  \[20\,\Omega \]
  done clear
  C)
  \[60\,\Omega \]
  done clear
  D)
  \[30\,\Omega \]
  done clear
  View Answer play_arrow

• question_answer133) 

  The galvanometer deflection, when key \[{{K}_{1}}\]is closed but \[{{K}_{2}}\] is open, equals \[{{\theta }_{0}},\] (see figure). On closing \[{{K}_{2}}\]also and adjusting \[{{R}_{2}}\] to \[5\Omega ,\]the deflection in galvanometer becomes\[\frac{{{\theta }_{0}}}{5}.\] The resistance of the galvanometer is, then, given by [Neglect the internal resistance of battery]                      [JEE Main 12-Jan-2019 Morning]

  A)
  \[25\Omega \]
  done clear
  B)
  \[22\Omega \]
  done clear
  C)
  \[5\Omega \]
  done clear
  D)
  \[12\Omega \]
  done clear
  View Answer play_arrow

• question_answer134) 

  In   the   figure shown, after the switch S is turned from position A to position B the energy dissipated in the circuit in terms of capacitance C and total charge Q is-                                             [JEE Main 12-Jan-2019 Morning]

  A)
  \[\frac{5}{8}\frac{{{Q}^{2}}}{C}\]
  done clear
  B)
  \[\frac{1}{8}\frac{{{Q}^{2}}}{C}\]
  done clear
  C)
  \[\frac{3}{8}\frac{{{Q}^{2}}}{C}\]
  done clear
  D)
  \[\frac{3}{4}\frac{{{Q}^{2}}}{C}\]
  done clear
  View Answer play_arrow

• question_answer135) An ideal battery of 4 V and resistance R are connected in series in the primary circuit of a potentiometer of length 1 m and resistance \[5\Omega .\] The value of R, to give a potential difference of mV across 10 cm of potentiometer wire is- [JEE Main 12-Jan-2019 Morning]
  A)
  \[490\,\Omega \]
  done clear
  B)
  \[495\,\Omega \]
  done clear
  C)
  \[395\,\Omega \]
  done clear
  D)
  \[480\,\Omega \]
  done clear
  View Answer play_arrow

• question_answer136) Two electric bulbs, rated at (25 W, 220 V) and (100 W, 220 V), are connected in series across a 220 V voltage source. If the 25 W and 100 W bulbs draw powers \[{{P}_{1}}\]and \[{{P}_{2}}\]respectively, then  [JEE Main 12-Jan-2019 Morning]
  A)
  \[{{P}_{1}}=9W,{{P}_{2}}=16W\]
  done clear
  B)
  \[{{P}_{1}}=16\,W,{{P}_{2}}=4W\]
  done clear
  C)
  \[{{P}_{1}}=4\,W,{{P}_{2}}=16W\]
  done clear
  D)
  \[{{P}_{1}}=16\,W,{{P}_{2}}=9W\]
  done clear
  View Answer play_arrow

• question_answer137) 

  In the figure shown, a circuit contains two identical resistors with resistance \[R=5\Omega \] and an inductance with L=2mH.

  An ideal battery of 15 V is connected in the circuit. What will be the current through the battery long after the switch is closed?            [JEE Main 12-Jan-2019 Morning]

  A)
  3 A
  done clear
  B)
  5.5 A
  done clear
  C)
  7.5 A
  done clear
  D)
  6 A
  done clear
  View Answer play_arrow

• question_answer138) 

  The charge on a capacitor plate in a circuit, as a function of time, is shown in the figure,

  [JEE Main 12-Jan-2019 Evening]

  What is the value of current at t = 4 s?

             
  A)
        \[3\mu A\]
  done clear
  B)
  zero
  done clear
  C)
  \[1.5\mu A\]
  done clear
  D)
  \[2\mu A\]
  done clear
  View Answer play_arrow

• question_answer139) 

  In the circuit shown, find C if the effective capacitance of the whole circuit is to be \[0.5\,\,\mu F.\]All values in the circuit are in \[\mu F.\]                   [JEE Main 12-Jan-2019 Evening]

  A)
  \[\frac{6}{5}\mu F\]
  done clear
  B)
  \[4\mu F\]
  done clear
  C)
  \[\frac{7}{11}\mu F\]
  done clear
  D)
  \[\frac{7}{10}\mu F\]
  done clear
  View Answer play_arrow

• question_answer140) 

  In the given circuit diagram, the currents, \[{{I}_{1}}=0.3A,{{I}_{4}}=0.8A\]and \[{{I}_{5}}=0.4A,\]are flowing as shown. The currents \[{{I}_{2}},{{I}_{3}}\]and \[{{I}_{6}},\]respectively, are-       [JEE Main 12-Jan-2019 Evening]

  A)
  \[1.1\text{ }A,\text{ }0.4\text{ }A,\text{ }0.4\text{ }A\]
  done clear
  B)
  \[-0.4A,\,\,0.4A,\,\,1.1A\]
  done clear
  C)
  \[1.1\text{ }A,\,\,-0.4\text{ }A,\,\,0.4\text{ }A\]
  done clear
  D)
  \[0.4A,\,\,1.1A,\,\,0.4A\]
  done clear
  View Answer play_arrow

• question_answer141) A galvanometer, whose resistance is 50 ohm, has 25 divisions in it. When a current of \[4\times {{10}^{-4}}\]A passes through it, its needle (pointer) deflects by one division. To use this galvanometer as a voltmeter of range 2.5 V, it should be connected to a resistance of- [JEE Main 12-Jan-2019 Evening]
  A)
  200 ohm
  done clear
  B)
  6250 ohm
  done clear
  C)
  6200 ohm
  done clear
  D)
  250 ohm
  done clear
  View Answer play_arrow

• question_answer142) 

  For the circuit shown, with \[{{R}_{1}}=1.0\Omega ,\]\[{{R}_{2}}=2.0\Omega ,{{E}_{1}}=2V\] and \[{{E}_{2}}={{E}_{3}}=4V,\]the potential difference between the points 'a' and 'b' is approximately (in V): [JEE Main 8-4-2019 Morning]

  A)
  2.7
  done clear
  B)
  3.3
  done clear
  C)
  2.3
  done clear
  D)
  3.7
  done clear
  View Answer play_arrow

• question_answer143) \[A200\Omega \] resistor has a certain color code. If one replaces the red color by green in the code, the new resistance will be : [JEE Main 8-4-2019 Morning]
  A)
  \[100\,\Omega \]
  done clear
  B)
  \[400\,\Omega \]
  done clear
  C)
  \[500\,\Omega \]
  done clear
  D)
  \[300\,\Omega \]
  done clear
  View Answer play_arrow

• question_answer144) 

  In the circuit shown, a four-wire potentiometer is made of a 400 cm long wire, which extends between A and B. The resistance per unit length of the potentiometer wire is \[r=0.01\Omega /cm.\]. If an ideal voltmeter is connected as shown with jockey J at 50 cm from end A, the expected

  reading of the voltmeter will be :-  [JEE Main 8-4-2019 Afternoon]

  A)
  0.20 V
  done clear
  B)
  0.25 V
  done clear
  C)
  0.75 V
  done clear
  D)
  0.50 V
  done clear
  View Answer play_arrow

• question_answer145) AA cell of internal resistance r drives current through an external resistance R. The power delivered by the cell to the external resistance will be maximum when :- [JEE Main 8-4-2019 Afternoon]
  A)
  R = 1000 r
  done clear
  B)
  R = 0.001 r
  done clear
  C)
  R = 2r
  done clear
  D)
  R = r
  done clear
  View Answer play_arrow

• question_answer146) The ratio of mass densities of nuclei of \[^{40}Ca\]and \[^{16}O\]is close to :-        [JEE Main 8-4-2019 Afternoon]
  A)
  1
  done clear
  B)
  2
  done clear
  C)
  0.1
  done clear
  D)
  5
  done clear
  View Answer play_arrow

• question_answer147) 

  In the figure shown, what is the current (in Ampere) drawn from the battery? You are given:

  \[{{R}_{1}}=15\Omega ,{{R}_{2}}=10\Omega ,{{R}_{3}}=20\Omega ,{{R}_{4}}=5\Omega ,\]

  \[{{R}_{5}}=25\Omega ,{{R}_{6}}=30\Omega ,E=15V\]           [JEE Main 8-4-2019 Afternoon]

  A)
  7/18
  done clear
  B)
  13/24
  done clear
  C)
  9/32
  done clear
  D)
  20/3
  done clear
  View Answer play_arrow

• question_answer148) 

  A wire of resistance R is bent to form a square ABCD as shown in the figure. The effective resistance between E and C is:

  (E is mid-point of arm CD) [JEE Main 9-4-2019 Morning]

  A)
  \[R\]
  done clear
  B)
  \[\frac{1}{16}R\]
  done clear
  C)
  \[\frac{7}{64}R\]
  done clear
  D)
  \[\frac{3}{4}R\]
  done clear
  View Answer play_arrow

• question_answer149) 

  Determine the charge on the capacitor in the following circuit : [JEE Main 9-4-2019 Morning]

  A)
  \[2\mu C\]
  done clear
  B)
  \[60\mu C\]
  done clear
  C)
  \[200\mu C\]
  done clear
  D)
  \[10\mu C\]
  done clear
  View Answer play_arrow

• question_answer150) A capacitor with capacitance \[5\mu F\]is charged to \[5\mu C.\]If the plates are pulled apart to reduce the capacitance to \[2\mu F,\]how much work is done? [JEE Main 9-4-2019 Morning]
  A)
  \[3.75\times {{10}^{6}}J\]
  done clear
  B)
  \[2.55\times {{10}^{6}}J\]
  done clear
  C)
  \[2.16\times {{10}^{6}}J\]
  done clear
  D)
  \[6.25\times {{10}^{6}}J\]
  done clear
  View Answer play_arrow

• question_answer151) A metal wire of resistance \[3\Omega \]is elongated to make a uniform wire of double its previous length. This new wire is now bent and the ends joined to make a circle. If two points on this circle make an angle 60° at the centre, the equivalent resistance between these two points will be :-       [JEE Main 9-4-2019 Afternoon]
  A)
  \[\frac{12}{5}\Omega \]
  done clear
  B)
  \[\frac{5}{3}\Omega \]
  done clear
  C)
  \[\frac{5}{2}\Omega \]
  done clear
  D)
  \[\frac{7}{2}\Omega \]
  done clear
  View Answer play_arrow

• question_answer152) In a conductor, if the number of conduction electrons per unit volume is \[8.5\times {{10}^{28}}\text{ }{{m}^{3}}\] and mean free time is 25ƒs (fem to second), it's approximate resistivity is :- \[\left( {{m}_{e}}=9.1\times {{10}^{31}}kg \right)\] [JEE Main 9-4-2019 Afternoon]
  A)
  \[{{10}^{-5}}\Omega m\]
  done clear
  B)
  \[{{10}^{-6}}\Omega m\]
  done clear
  C)
  \[{{10}^{-7}}\Omega m\]
  done clear
  D)
  \[{{10}^{-8}}\Omega m\]
  done clear
  View Answer play_arrow

• question_answer153) A current of 5 A passes through a copper conductor (resistivity\[=1.7\times {{10}^{-8}}\Omega m\]) of radius of cross-section 5 mm. Find the mobility of the charges if their drift velocity is \[=1.1\times {{10}^{-3}}m/s.\] [JEE Main 10-4-2019 Morning]
  A)
  \[1.3\text{ }{{m}^{2}}/Vs\]
  done clear
  B)
  \[1.5\text{ }{{m}^{2}}/Vs\]
  done clear
  C)
  \[1.8\text{ }{{m}^{2}}/Vs\]
  done clear
  D)
  \[1.0\text{ }{{m}^{2}}/Vs\]
  done clear
  View Answer play_arrow

• question_answer154) 

  In an experiment, the resistance of a material is plotted as a function of temperature (in some range). As shown in the figure, it is a straight line. One may conclude that : [JEE Main 10-4-2019 Morning]

  A)
  \[R(T)=\frac{{{R}_{0}}}{{{T}^{2}}}\]
  done clear
  B)
  \[R(T)={{R}_{0}}{{e}^{-{{T}^{2}}/T_{0}^{2}}}\]
  done clear
  C)
  \[R(T)={{R}_{0}}{{e}^{-T_{0}^{2}/T_{{}}^{2}}}\]
  done clear
  D)
  \[R(T)={{R}_{0}}{{e}^{T_{{}}^{2}/T_{0}^{2}}}\]
  done clear
  View Answer play_arrow

• question_answer155) 

  In the given circuit, an ideal voltmeter connected across the \[10\Omega \]resistance reads 2V. The internal resistance r, of each cell is: [JEE Main 10-4-2019 Morning]

  A)
  \[1\Omega \]
  done clear
  B)
  \[1.5\Omega \]
  done clear
  C)
  \[0\Omega \]
  done clear
  D)
  \[0.5\Omega \]
  done clear
  View Answer play_arrow

• question_answer156) Space between two concentric conducting spheres of radii a and \[b\left( b>a \right)\] is filled with a medium of resistivity \[\rho \]. The resistance between the two spheres will be : [JEE Main 10-4-2019 Afternoon]
  A)
  \[\frac{\rho }{4\pi }\left( \frac{1}{a}-\frac{1}{b} \right)\]
  done clear
  B)
  \[\frac{\rho }{2\pi }\left( \frac{1}{a}-\frac{1}{b} \right)\]
  done clear
  C)
  \[\frac{\rho }{2\pi }\left( \frac{1}{a}+\frac{1}{b} \right)\]
  done clear
  D)
  \[\frac{\rho }{4\pi }\left( \frac{1}{a}+\frac{1}{b} \right)\]
  done clear
  View Answer play_arrow

• question_answer157) Which of the following combinations has the dimension of electrical resistance (\[{{\varepsilon }_{0}}\]is the permittivity of vacuum and \[{{\mu }_{0}}\]is the permeability of vacuum)?         [JEE Main Held on 12-4-2019 Morning]
  A)
  \[\sqrt{\frac{{{\varepsilon }_{0}}}{{{\mu }_{0}}}}\]
  done clear
  B)
  \[\frac{{{\mu }_{0}}}{{{\varepsilon }_{0}}}\]
  done clear
  C)
  \[\sqrt{\frac{{{\mu }_{0}}}{{{\varepsilon }_{0}}}}\]      
  done clear
  D)
  \[\frac{{{\varepsilon }_{0}}}{{{\mu }_{0}}}\]
  done clear
  View Answer play_arrow

• question_answer158) 

  To verify Ohm's law, a student connects the voltmeter across the battery as, shown in the figure. The measured voltage is plotted as a function of the current, and the following graph is obtained:

  If V0 is almost zero, identify the correct statement:  [JEE Main Held on 12-4-2019 Morning]

  A)
  The value of the resistance R is \[1.5\Omega \]
  done clear
  B)
  The emf of the battery is 1.5 V and the value of R is \[1.5\Omega \]
  done clear
  C)
  The emf of the battery is 1.5 V and its internal resistance is \[1.5\Omega \]
  done clear
  D)
  The potential difference across the battery is 1.5 V when it sends a current of 1000 mA.
  done clear
  View Answer play_arrow

• question_answer159) 

  The resistive network shown below is connected to a D.C. source of 16V. The power consumed by the network is 4 Watt. The value of R is : [JEE Main Held on 12-4-2019 Morning]

  A)
  \[8\Omega \]
  done clear
  B)
  \[6\Omega \]
  done clear
  C)
  \[1\Omega \]
  done clear
  D)
  \[16\Omega \]
  done clear
  View Answer play_arrow

• question_answer160) 

  In the given circuit, the charge on \[4\mu F\]capacitor will be:      [JEE Main 12-4-2019 Afternoon]

  A)
  \[5.4\mu C\]
  done clear
  B)
  \[24\mu C\]
  done clear
  C)
  \[13.4\mu C\]
  done clear
  D)
  \[9.6\mu C\]
  done clear
  View Answer play_arrow

• question_answer161) 

  The current \[{{I}_{1}}\] (in A) flowing through \[1\Omega \] resistor in the following circuit is: [JEE MAIN Held on 07-01-2020 Morning]

  A)
  0.5
  done clear
  B)
  0.4
  done clear
  C)
  0.25
  done clear
  D)
  0.2
  done clear
  View Answer play_arrow

• question_answer162) In a building there are 15 bulbs of 45 W, 15 bulbs of 100 W, 15 small fans of 10 W and 2 heaters of 1 kW. The voltage of electric main is 220 V. The minimum fuse capacity (rated value) of the building will be [JEE MAIN Held on 07-01-2020 Evening]
  A)
  15 A    
  done clear
  B)
  10 A
  done clear
  C)
  20 A    
  done clear
  D)
  25 A
  done clear
  View Answer play_arrow

• question_answer163) The balancing length for a cell is 560 cm in a potentiometer experiment. When an external resistance of \[10\,\Omega \]  is connected in parallel to the cell, the balancing length changes by 60 cm. If the internal resistance of the cell is \[\frac{N}{10}\,\Omega \], where N is an integer then value of N is _________. [JEE MAIN Held on 07-01-2020 Evening]
  View Answer play_arrow

• question_answer164) The length of a potentiometer wire is 1200 cm and it carries a current of 60 mA. For a cell of emf 5 V and internal resistance of \[20,\Omega \]the null point on it is found to be at 1000 cm. The resistance of whole wire is : [JEE MAIN Held On 08-01-2020 Morning]
  A)
  \[80\,\Omega \]
  done clear
  B)
  \[100\,\Omega \]
  done clear
  C)
  \[60\,\Omega \]
  done clear
  D)
  \[120\,\Omega \]
  done clear
  View Answer play_arrow

• question_answer165) Four resistances of 15 \[\Omega \], 12 \[\Omega \], 4 \[\Omega \] and 10 \[\Omega \]. Respectively in cyclic order to form Wheatstone’s network. The resistance that is to be connected in parallel with the resistance of 10 \[\Omega \] to balance the network is _________\[\Omega \]. [JEE MAIN Held On 08-01-2020 Morning]
  View Answer play_arrow

• question_answer166) A galvanometer having a coil resistance \[100\,\,\Omega \] gives a full scale deflection when a current of 1 mA is passed through it. What is the value of the resistance which can convert this galvanometer into a voltmeter giving full scale deflection for a potential difference of 10 V? [JEE MAIN Held on 08-01-2020 Evening]
  A)
  \[10\text{ k}\,\Omega \]
  done clear
  B)
  \[9.9\text{ }k\Omega \]
  done clear
  C)
  \[8.9\text{ }k\Omega \]
  done clear
  D)
  \[7.9\text{ }k\Omega \]
  done clear
  View Answer play_arrow

• question_answer167) The series combination of two batteries, both of the same emf 10 V, but different internal resistance of \[20\text{ }\Omega \] and\[\text{5 }\Omega \], is connected to the parallel combination of two resistors \[\text{30 }\Omega \] and \[\text{R }\Omega \]. The voltage difference across the battery of internal resistance \[20\text{ }\Omega \] is zero, the value of R\[\left( \text{in }\Omega  \right)\] is _______.   [JEE MAIN Held on 08-01-2020 Evening]
  View Answer play_arrow

• question_answer168) 

  In the given circuit diagram, a wire is joining points B and D. The current in this wire is:

  [JEE MAIN Held on 09-01-2020 Morning]

             
  A)
  0.4 A
  done clear
  B)
  4 A
  done clear
  C)
  2 A
  done clear
  D)
  zero
  done clear
  View Answer play_arrow

• question_answer169) 

  In a meter bridge experiment S is a standard resistance. R is a resistance wire. It is found that balancing length is\[l=25\text{ }cm\]. If R is replaced by a wire of half length and half diameter that of R of same material, then the balancing distance \[l'\] (in cm) will now be______. [JEE MAIN Held on 09-01-2020 Evening]

  View Answer play_arrow