question_answer2) Which one of the following graph represents the variation of maximum kinetic energy \[({{E}_{k}})\] of the emitted electrons with frequency v in photoelectric effect correctly?
question_answer3) A and B are two metals with threshold frequencies \[1.8\times {{10}^{14}}Hz\] and \[2.2\times {{10}^{14}}Hz.\]Two identical photons of energy 0.825 eV each are incident on them. Then photoelectrons are emitted by (Take\[h=6.6\times {{10}^{-34}}J-s\])
question_answer5) In the Wheatstone's network given, \[P=10\Omega \], \[Q=20\,\Omega ,\,\,R=15\,\Omega ,\,\,S=30\,\Omega \] the current passing through the battery (of negligible internal resistance) is
question_answer6) Electrons in a certain energy level \[n={{n}_{1}}\], can emit 3 spectral lines. When they are in another energy level, \[n={{n}_{2}}\], they can emit 6 spectral lines. The orbital speed of the electrons in the orbits are in the ratio
question_answer7) A circular coil carrying a certain current produces a magnetic field \[{{B}_{0}}\] at its centre. The coil is now rewound so as to have 3 turns and the same current is passed through it. The new magnetic field at the centre is
question_answer8) A proton and a deuteron with the same initial kinetic energy enter a magnetic field in a direction perpendicular to the direction of the field. The ratio of the radii of the circular trajectories described by them is
question_answer9) Two tangent galvanometers A and B have coils of radii 8 cm and 16 cm respectively and resistance \[8\Omega \] each. They are connected in parallel with a cell of emf 4 V and negligible internal resistance. The deflections produced in the tangent galvanometers A and B are \[{{30}^{o}}\]and \[{{60}^{o}}\] respectively. If A has 2 turns, then B must have
question_answer10) A charged particle is moving in a magnetic field of strength B perpendicular to the direction of the field. If q and m denote the charge and mass of the particle respectively, then the frequency of rotation of the particle is
question_answer11) Two identical capacitors each of capacitance \[5\mu F\] are charged to potentials 2 kV and 1 kV respectively. Their -ve ends are connected together. When the +ve ends are also connected together, the loss of energy of the system is
question_answer12) A parallel plate capacitor with air as the dielectric has capacitance C. A slab of dielectric constant K and having the same thickness as the separation between the plates is introduced so as to fill one-fourth of the capacitor as shown in the figure. The new capacitance will be
question_answer13) A current of 5 A is passing through a metallic wire of cross-sectional area \[4\times {{10}^{-6}}{{m}^{2}}\]. If the density of charge carriers of the wire is\[5\times {{10}^{26}}{{m}^{-3}}\], the drift velocity of the electrons will be
question_answer16) A and D are two infinitely long straight parallel conductors. C is another straight conductor of length 1m kept parallel to A and B as shown in the figure. Then the force experienced by C is
question_answer17) An electric bulb has a rated power of 50 W s: 100 V. If it is used on an AC source 200 V 50 Hz, a choke has to be used in series with is This choke should have an inductance of
question_answer18) An inductance of \[\left( \frac{200}{\pi } \right)\,mH\], a capacitance of \[\left( \frac{{{10}^{-3}}}{\pi } \right)F\]and a resistance of \[10\,\Omega \] are connected in series with an AC source 220 V, 50 Hz. The phase angle of the circuit is
question_answer19) A step-down transformer reduces the voltage of a transmission line from 2200 V to 220 V. The power delivered by it is 880 W and its efficiency is 88%. The input current is
question_answer22) Light from two coherent sources of the same amplitude A and wavelength \[\lambda \] illuminates the screen. The intensity of the central maximum is \[{{I}_{0}}\]. If the sources were incoherent, the intensity at the same point will be
question_answer23) In Young's double slit experiment with sodium vapour lamp of wavelength 589 nm and the slits 0.589 mm apart, the half angular width of the central maximum is
question_answer24) A single slit Fraunhofer diffraction pattern is formed with white light. For what wavelength of light the third secondary maximum in the diffraction pattern coincides with the second secondary maximum in the pattern for red light of wavelength \[6500\overset{o}{\mathop{A}}\,\]?
question_answer25) The head lights of a jeep are 1.2 m apart. If the pupil of the eye of an observer has a diameter of mm and light of wavelength 5896 \[{{A}^{o}}\]is used, what should be the maximum distance of the jeep from the observer if the two head lights are just separated?
question_answer26) The de-Broglie wavelength of a proton (charge \[=1.6\times {{10}^{-19}}C\], mass \[=1.6\times {{10}^{-27}}kg\]) accelerated through a potential difference of 1 kV is
question_answer28) A radioactive substance contains 10000 nuclei and its half-life period is 20 days. The number of nuclei present at the end of 10 days is
question_answer31) A ray of light is travelling from glass to air. (refractive index of glass = 1.5). The angle of incidence is \[{{50}^{o}}\]. The deviation of the ray is
question_answer32) A vessel of height 2d is half-filled with a liquid of refractive index \[\sqrt{2}\] and the other half with a liquid of refractive index n (the given liquids are immiscible). Then the apparent depth of the inner surface of the bottom of the vessel (neglecting the thickness of the bottom of the vessel) will be
question_answer33) A ray of light is incident normally on one face of a right angled isosceles prism. It then grazes the hypotenuse. The refractive index of the material of the prism is
question_answer34) Two thin equiconvex lenses each of focal length 0.2 m are placed coaxially with their optic centres 0.5 m apart. Then the focal length of the combination is
question_answer35) A prism of a certain angle deviates the red and blue rays by \[{{8}^{o}}\] and \[{{12}^{o}}\] respectively. Another prism of the same angle deviates the red and blue rays by \[{{10}^{o}}\] and \[{{14}^{o}}\] respectively. The prisms are small angled and made of different materials. The dispersive powers of the materials of the prisms are in the ratio
question_answer36) When the angle of incidence is \[{{60}^{o}}\] on the surface of a glass slab, it is found that the reflected ray is completely polarised. The velocity of light in glass is
question_answer37) A 20 cm length of a certain solution causes right handed rotation of \[{{38}^{o}}\]. A 30 cm length of another solution causes left handed rotation of \[{{24}^{o}}\]. The optical rotation caused by 30 cm length of a mixture of the above solutions in the volume ratio \[1:2\] is
question_answer38) Two identical charges repel each other with a force equal to 10 mg wt when they are 0.6 m a part in air \[(g=10\text{ }m{{s}^{-2}})\]. The value of each charge is
question_answer39) The potential of the electric Held produced by point charge at any point \[(x,y,z)\] is given by\[V=3{{x}^{2}}+5\], where \[x,y\] are in metres and V is m volts. The intensity of the electric Held at \[(-2,1,0)\] is
question_answer42) The maximum height attained by a projectile when thrown at an angle \[\theta \] with the horizontal is found to be half the horizontal range. Then 0 is equal to
question_answer43) A shell of mass 20 kg at rest explodes into two fragments whose masses are in the ratio \[2:3\]. The smaller fragment moves with a velocity of\[6\,\,m{{s}^{-1}}\]. The kinetic energy of the larger fragment is
question_answer45) The acceleration due to gravity becomes \[\left( \frac{g}{2} \right)\] (g = acceleration due to gravity on the surface of the earth) at a height equal to
question_answer46) The cylindrical tube of a spray pump has a cross-section of \[8\text{ }c{{m}^{2}}\], one end of which has 40 fine holes each of area \[{{10}^{-8}}{{m}^{2}}\]. If the liquid flows inside the tube with a speed of\[0.15\text{ }m\text{ }mi{{n}^{-1}}\], the speed with which the liquid is ejected through the holes is
question_answer47) During an adiabatic process, the cube of the pressure is found to be inversely proportional to the fourth power of the volume. Then the ratio of specific heats is
question_answer48) Two identical rods AC and CB made of two different metals having thermal conductivities in the ratio \[2:3\] are kept in contact with each other at the end C as shown in the figure. A is at \[{{100}^{o}}C\] and B is at \[{{25}^{o}}C\]. Then the junction C is at
question_answer49) 310 J of heat is required to raise the temperature of 2 moles of an ideal gas at constant pressure from \[{{25}^{o}}C\] to \[{{35}^{o}}C\]. The amount of heat required to raise the temperature of the gas through the same range at constant volume is
question_answer50) A Carnot's engine operates with source at \[{{127}^{o}}C\] and sink at \[{{27}^{o}}C\]. If the source supplies 40 kJ of heat energy, the work done by the engine is
question_answer52) The ratio of the velocity of sound in hydrogen\[\left( \gamma =7/5 \right)\]to that in helium \[\left( \gamma =\frac{5}{3} \right)\] at the same temperature is
question_answer53) An engine moving towards a wall with a velocity \[50\text{ }m{{s}^{-1}}\] emits a note of 1.2 kHz. Speed of sound in air is \[350\text{ }m{{s}^{-1}}\]. The frequency of the note after reflection from the wall as heard by the driver of the engine is
question_answer54) A glass tube is open at both the ends. A tuning fork of frequency \[f\] resonates with the air column inside the tube. Now the tube is placed vertically inside water so that half the length of the tube is filled with water. Now the air column inside the tube is in unison with another fork of frequency \[f'\]. Then
question_answer55) The surface temperature of the sun which has maximum energy emission at 500 nm is 6000 K. The temperature of a star which has maximum energy emission at 400 nm will be
question_answer59) In a reverse biased diode when the applied voltage changes by 1 V, the current is found to change by \[0.5\,\mu A\] The reverse bias resistance of the diode is
question_answer85) A body of mass 10 mg is moving with a velocity of \[100\,\,m{{s}^{-1}}\]. The wavelength of de-Broglie wave associated with it would be \[(h=6.63\times {{10}^{-34}}Js)\]
question_answer87) The number of antibonding electron pairs in \[O_{2}^{2-}\] molecular ion on the basis of molecular orbital theory is (Atomic number of 0 is 18.)
question_answer91) During the extraction of gold the following reactions take place \[Au+C{{N}^{-}}+{{H}_{2}}O\xrightarrow{{{O}_{2}}}[X]\]\[[X]+Zn\xrightarrow{{}}[Y]+Au\]X and Y are respectively
A)
\[{{[Au{{(CN)}_{2}}]}^{-}}\] and \[{{[Zn{{(CN)}_{6}}]}^{4-}}\]
doneclear
B)
\[{{[Au{{(CN)}_{4}}]}^{2-}}\] and \[{{[Zn{{(CN)}_{4}}]}^{2-}}\]
doneclear
C)
\[{{[Au{{(CN)}_{4}}]}^{3-}}\] and \[{{[Zn{{(CN)}_{4}}]}^{2-}}\]
doneclear
D)
\[{{[Au{{(CN)}_{2}}]}^{-}}\] and \[{{[Zn{{(CN)}_{4}}]}^{2-}}\]
question_answer100) What is the equivalent weight of \[SnC{{l}_{2}}\] in the following reaction\[SnC{{l}_{2}}+C{{l}_{2}}\xrightarrow{{}}SnC{{l}_{4}}?\]
question_answer119) Considering the reaction \[C(s)+{{O}_{2}}(g)\] \[\xrightarrow{{}}C{{O}_{2}}(g)+393.5\,kJ\] the signs of \[\Delta H,\,\,\Delta S\] and \[\Delta G\] respectively are
question_answer121) If \[\vec{a}=2\hat{i}+3\hat{j}-k,\] \[\vec{b}=\hat{i}+2\hat{j}-5\hat{k},\] \[\vec{c}=3\hat{i}+5\hat{j}-\hat{k},\]Then a vector perpendicular to \[\vec{a}\]and in the plane containing \[\overrightarrow{b}\] and \[\overrightarrow{c}\] is
question_answer122) \[\overrightarrow{OA}\] and \[\overrightarrow{BO}\] are two vectors of magnitudes 5 and 6 respectively. If Z \[\angle BOA={{60}^{o}},\]then \[\overrightarrow{OA}.\overrightarrow{OB}\]is equal to
question_answer131) A graph G has ?m' vertices of odd degree and ?n' vertices of even degree. Then which of the following statements is necessarily true?
question_answer132) If P is any point on the ellipse \[\frac{{{x}^{2}}}{36}+\frac{{{y}^{2}}}{16}=1,\] and S and S' are the foci, then \[PS+PS'\]is equal to
question_answer136) If \[A\left[ \begin{matrix} 1 & -1 & 1 \\ 2 & 1 & -3 \\ 1 & 1 & 1 \\ \end{matrix} \right],10B=\left[ \begin{matrix} 4 & 2 & 2 \\ -5 & 0 & \alpha \\ 1 & -2 & 3 \\ \end{matrix} \right]\] and B is the inverse of A, then the value of \[\alpha \] is
question_answer137) If \[A=\left[ \begin{matrix} 0 & x & 16 \\ x & 5 & 7 \\ 0 & 9 & x \\ \end{matrix} \right]\] is singular, then the possible values of x are
question_answer147) In the group \[(G,\,\,{{\otimes }_{15}}),\] where \[G=\{3,6,9,12\},\]\[{{\otimes }_{15}}\]is multiplication modulo 15, the identity element is
question_answer149) If \[\vec{a}\] and \[\vec{b}\] are vectors such that \[|\vec{a}+\vec{b}|\]\[=|\vec{a}-\vec{b}|,\] then the angle between \[\vec{a}\] and \[\vec{b}\]is
question_answer156) \[{{x}^{2}}+{{y}^{2}}-6x-6y+4=0,\] \[{{x}^{2}}+{{y}^{2}}-2x\]\[-4y+3=0,\] \[{{x}^{2}}+{{y}^{2}}+2kx+2y+1=0\]. If the radical centre of the above three circles exists, then which of the following cannot be the value off k?
question_answer157) If the circles \[{{x}^{2}}+{{y}^{2}}-2x-2y-7=0\]and \[{{x}^{2}}+{{y}^{2}}+4x+2y+k=0\] cut orthogonally, then the length of the common chord of the circles is
question_answer160) If the area of the auxiliary circle of the ellipse \[\frac{{{x}^{2}}}{{{a}^{2}}}+\frac{{{y}^{2}}}{{{b}^{2}}}=1\] \[(a>b)\] is twice the area of the ellipse, then the eccentricity of the ellipse is
question_answer163) OA and OB are two roads enclosing an angle of\[{{120}^{o}}\]. X and y start from ?O' at the same time. X travels along OA with a speed of 4 km/h and Y travels along OB with a speed of 3 km/h. The rate at which the shortest distance between X and V is increasing after \[1\text{ }h\]is
question_answer168) If the function \[f(x)=\left\{ \begin{matrix} \frac{1-\cos \,\,x}{{{x}^{2}}} & for & x\ne 0 \\ k & for & x=0 \\ \end{matrix} \right.\]is continuous at \[x=0,\] then the value of k is
question_answer169) If \[1,\,\omega ,\,{{\omega }^{2}}\] are the cube roots of unity then \[(1+\omega )(1+{{\omega }^{2}})(1+{{\omega }^{4}})(1+{{\omega }^{8}})\]is equal to
question_answer175) The order and degree of the differential equation \[{{\left[ 1+{{\left( \frac{dy}{dx} \right)}^{5}} \right]}^{\frac{1}{3}}}=\frac{{{d}^{2}}y}{d{{x}^{2}}}\] are respectively