The length of a potentiometer wire is I. A cell of emf \[\varepsilon \] is balanced at a length \[l/5\]from the positive end of the wire. If length of the wire is increased by \[l/2\]. At what distance will the same cell give a balance point?
A body A starts from rest with an acceleration ay After 2 seconds, another body B starts from rest with an acceleration \[{{a}_{1}}\]. If they travel equal distances in the 5th second, after the start of A, then the ratio \[{{a}_{1}}:{{a}_{2}}\]is equal to
A particle of charge q and mass m moves in a circular orbit of radius r with angular speed co. The ratio of the magnitude of its magnetic moment to that of its angular momentum depends on
A machine gun is mounted on a 2000 kg car on a horizontal frictionless surface. At some instant, the gun fires 10 bullets/second and each of mass 10 g with a velocity of \[500\,\text{m}\,{{\text{s}}^{-1}}\]. The acceleration of the car is
A bomb moving with velocity \[(40\hat{i}+50\hat{j}-25\hat{k})m{{s}^{-1}}\]explode into two pieces of mass ratio 1 : 4. After explosion the smaller piece moves away with velocity\[(200\hat{i}+70\hat{j}+15\hat{k})m{{s}^{-1}}\]. The velocity of larger piece after explosion is
A ray of light is incident normally on one of the faces of a prism of apex angle \[30{}^\circ \]and refractive index \[\sqrt{2}\]The angle of deviation of the ray is
Particles of masses m, 2m, 3m ... nm grams are placed on the same line at distance \[l,2l,3l...nlcm\] from a fixed point. The distance of centre of mass of the particles from the fixed point in centimetre is
When one of the slits of Youngs experiment is covered with a transparent sheet of thickness 4.8 mm, the central fringe shifts to a position originally occupied by the 30th bright fringe. What should be the thickness of the sheet if the central fringe has to shift to the position occupied by 20th bright fringe?
The electric field (in \[\text{N}{{\text{C}}^{-1}}\]) in an electromagnetic wave is given by \[E=50\sin \omega \left( t-\frac{x}{c} \right)\]. The energy stored in a cylinder of cross- section \[10\text{c}{{\text{m}}^{2}}\]and length 100 cm along the x-axis will be
A common emitter amplifier has a voltage gain of 50, an input impedance of \[100\Omega \]and an output impedance of \[200\Omega \]The power gain of the amplifier is
The Poisson?s ratio of a material is 0.4. If a force is applied to a wire of this material, there is a decrease of cross-sectional area by 2%. The percentage increase in its length is
The mass of deuteron \[{{(}_{1}}{{H}^{2}})\]nucleus is 2.014102 u. If the masses of proton and neutron are 1.007825 u and 1.008665 u respectively, nucleus the binding energy per nucleon of \[_{1}{{H}^{2}}\] nucleus is
An electric dipole of length 1 cm is placed with the axis making an angle of \[30{}^\circ \]with an electric field of strength \[{{10}^{4}}\text{N}\,{{\text{C}}^{-1}}\]. If it experiences a torque of \[10\sqrt{2}\,\text{N}\,\text{m,}\]the potential energy of the dipole is
A parallel plate capacitor is maintained at a certain potential difference. When a 3 mm thick slab is introduced between the plates, in order to maintain the same potential difference, the distance between the plates is increased by 2.4 mm. The dielectric constant of the slab is __.
A silver sphere of radius 1 cm and work function 4.7 eV is suspended from an insulating thread in free-space. It is under continuous illumination of light of wavelength 200 nm. As photoelectrons are emitted, the sphere gets charged and acquires a potential. The maximum number of photoelectrons emitted from the sphere is \[A\times {{10}^{7}}\](where 1 < A < 10). The value of Z is ____.
The activity of a freshly prepared radioactive sample is \[{{10}^{10}}\]disintegrations per second, whose mean life is \[{{10}^{9}}\] s. The mass of an atom of this radioisotope is\[{{10}^{-25}}\] kg. The mass of the radioactive sample is ____ mg.
In a car race sound signals emitted by the two cars are detected by the detector on the straight track at the end point of the race. Frequency observed are 330 Hz and 360 Hz and the original frequency is 300 Hz of both cars. Race ends with the separation of 100 m between the cars. Assume both cars move with constant velocity and velocity of sound is 330\[\text{m}\,{{\text{s}}^{-1}}\]. The time taken by winning car is ____ s.
A solution containing \[2.675\text{ }g\]of \[CoC{{l}_{2}}.6N{{H}_{3}}\] was passed through a cation exchanger. The solution obtained gave \[4.305\text{ }g\]of \[AgCl\]precipitate with \[AgN{{O}_{3}}\]solution. Determine the formula of the complex. (\[{{M}_{wt}}\] of\[CoC{{l}_{3}}.6N{{H}_{3}}=267.5\])
In the following reactions A, B, C and D are, respectively, \[\underset{(blue)}{\mathop{CuS{{O}_{4}}.5{{H}_{2}}O}}\,\underset{(bluish\,\,white)}{\mathop{\xrightarrow{100{}^\circ C}A\xrightarrow{230{}^\circ C}}}\,B\underset{(Black)}{\mathop{\xrightarrow{800{}^\circ C}C+D}}\,+\frac{1}{2}{{O}_{2}}\]
A)
A - \[CuS{{O}_{4}}.4{{H}_{2}}O\] B - \[CuS{{O}_{4}}\] C - \[CuO\] D - \[S{{O}_{3}}\]
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B)
A - \[CuS{{O}_{4}}.2{{H}_{2}}O\] B - \[CuS{{O}_{4}}.{{H}_{2}}O\] C - \[CuS{{O}_{4}}\] D - \[CuO\]
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C)
A - \[CuS{{O}_{4}}.3{{H}_{2}}O\] B - \[CuS{{O}_{4}}.\]\[2{{H}_{2}}O\] C - \[CuO\] D - \[S{{O}_{2}}\]
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D)
A - \[CuS{{O}_{4}}.{{H}_{2}}O\] B - \[CuO\] C - \[S{{O}_{3}}\] D - \[Cu{{O}_{2}}\]
Two flasks A and B have equal volumes. A is maintained at \[300\text{ }K\]and B at\[600\text{ }K\]. Flask A contains \[{{H}_{2}}\] gas, flask B has an equal mass of \[C{{H}_{4}}\]gas. Assuming ideal behaviour for both the gases. Select the INCORRECT statement
A)
\[{{N}_{A}}=8{{N}_{B}}\] (where \[{{N}_{A}}\]and \[{{N}_{B}}\] are the number of molecules in flask A and B respectively).
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B)
\[{{p}_{A}}=4{{p}_{B}}\] (where \[{{p}_{A}}\] and \[{{p}_{B}}\] are the pressure in flask A and B respectively)
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C)
\[{{({{\mu }_{av}})}_{A}}=4{{({{\mu }_{av}})}_{B}}\] and \[{{({{\mu }_{av}})}_{A}}\] are \[{{({{\mu }_{av}})}_{B}}\] average speed of molecules in flask A and B respectively)
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D)
\[{{X}_{A}}=16\,{{X}_{B}}\] (where \[{{X}_{A}}\] and \[{{X}_{B}}\] are the number of collisions per unit area per unit time in flask A and B respectively).
Select the INCORRECT statement about biological importance of \[N{{a}^{\oplus }}\] and \[{{K}^{\oplus }}\] ions.
A)
Normal human being contains amount of potassium greater than the amount of sodium.
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B)
\[N{{a}^{\oplus }}\]ions are found primarily outside the cells in blood plasma and other interstitial fluids while K® ions are found inside the cell.
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C)
\[{{K}^{\oplus }}\] ions participate in the transmission of nerve signals and in the transport of sugars and amino acids into cells. \[N{{a}^{\oplus }}\] ions activate many enzymes, participate in the oxidation of glucose to produce ATP.
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D)
\[N{{a}^{\oplus }}\]ions are present to the extent of \[143\text{ }m\text{ }mol\text{ }{{L}^{-1}}\] in blood plasma whereas concentration of \[{{K}^{\oplus }}\] is only \[5\text{ }mmol\text{ }{{L}^{-1}}\] in RBC.
\[{{K}_{c}}\] for the following reaction is This reaction is set-up in aqueous medium. \[1\text{ }mol\]of \[{{I}_{2}}\] and \[0.5\text{ }mol\text{ }{{I}^{\bigcirc -}}\]in 1 L flask, after equilibrium is reached, excess of \[AgN{{O}_{3}}\]gave \[0.25\text{ }mol\]of yellow precipitate.
Two weak acids HX and HY have \[{{K}_{a}}\] values \[1.75\times {{10}^{-5}}\]and \[1.3\times {{10}^{-5}},\] respectively, at a certain temperature. An equimolar solution for mixture of two acids is partially neutralised by\[NaOH\]. How is the ratio of the contents of \[{{X}^{\bigcirc -}}\] and \[{{Y}^{\bigcirc -}}\] ions related to the values and molarity?
A)
\[\left[ \frac{\alpha }{1-\alpha } \right]=\frac{1.75}{1.3}\times \left[ \frac{\alpha '}{1-\alpha '} \right],\]\[0,\] where \[\alpha \] and \[\alpha \] are ionised fractions of the acids HX and HY respectively.
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B)
The ratio is unrelated to the \[{{K}_{a}}\] values.
In the case of a first order reaction, the time required for \[93.75%\] of reaction to take place is x times that required for half of the reaction. Find the value of x.
\[50\text{ }mL\]of ozone, \[({{O}_{3}})\] at STP was passed through \[50\text{ }mL\]of '5 volume' \[{{H}_{2}}{{O}_{2}}\] solution. The volume strength of \[{{H}_{2}}{{O}_{2}}\] after the reaction is ______.
Bond dissociation energy of XY, \[{{X}_{2}}\], and \[{{Y}_{2}}\] (all diatomic molecules) are in the ratio of \[1:1:0.5\]and \[\Delta {{H}_{f}}\] of XY is \[-100\,kJmo{{l}^{-1}},\] The bond dissociation energy of \[{{X}_{2}}\] is \[100x\]. Find the value of x.
The energy required to ionise a helium atom is equal to\[24.6\text{ }eV\]. The energy required to remove both the electrons from the helium atom in eV is ______.
A certain substance A tetra merises in water to the extent of 80%. A solution of \[2.5\text{ }g\]of A in 100 g of water lowers the freezing point by\[0.3{}^\circ C\]. The molar mass of A is ______.
If \[f:\left[ -6,6 \right]\to R\] is defined by \[f(x)={{x}^{2}}-3\]for \[x\in R\], then \[\left( fofof \right)\,\left( -1 \right)+\left( fofof \right)\,\left( 0 \right)+\left( fofof \right)\,\left( 1 \right)\] is equal to
Let \[\alpha \] and \[\beta \]be the roots of \[a{{x}^{2}}+bx+c=0,\] Then \[\underset{x\to \alpha }{\mathop{\lim }}\,\,\frac{1-\cos (a{{x}^{2}}+bx+c)}{{{(x-\alpha )}^{2}}}\]is equal to:
If \[4\hat{i}+7\hat{j}+8\hat{k},\] \[2\hat{i}+3\hat{j}+4\hat{k}\] and \[2\hat{i}+5\hat{j}+7\hat{k}\] are the position vectors of the vertices A, B and C respectively of triangle ABC. The position vector of the point where the bisector of angle A meets BC is :
Given vertices \[A(1,1),\] \[B(4,-2)\] and \[C(5,5)\] of a triangle, then the equation of the perpendicular dropped from C to the interior bisector of the angle A is
The angular elevation of a tower CD at a point A due south of it is \[60{}^\circ \]and at a point B due west of A, the elevation is \[30{}^\circ \]. If \[AB=3\text{ }km,\]the height of the tower is
A stone is dropped into a quiet lake and waves move in a circle at a speed of \[3.5\text{ }cm/sec.\]At the instant when the radius of the circular wave is\[7.5\text{ }cm\]. Then, the rate of increasing in the enclosed area is \[k\,\pi ,\] then k is
Let f: \[R\to R\]be a differentiable function and \[f(1)=4.\]. Then the value of \[\underset{x\to 1}{\mathop{\lim }}\,\,\frac{\int\limits_{4}^{f(x)}{2t\,dt}}{x-1}.\]if \[(1)=2\]is -
One dice is thrown three times and the sum of the thrown numbers is 15. If the probability for which number 4 appears in first throw is p, then \[\frac{1}{p}\] is: