Current Electricity

1. A.
   100%
2. B.
   200%
3. C.
   300%
4. D.
   400%

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1. A.
   $\frac{1}{2}(\rho_1 + \rho_2)$
2. B.
   $\rho_1 + \rho_2$
3. C.
   $\sqrt{\rho_1 \rho_2}$
4. D.
   $2\,(\rho_1 + \rho_2)$

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1. A.
   1%
2. B.
   4%
3. C.
   -4%
4. D.
   2%

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1. A.
   $\frac{e}{n}$
2. B.
   $ne$
3. C.
   $\frac{ne}{r}$
4. D.
   $\frac{e}{nr}$

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1. A.
   Drift velocity only
2. B.
   Thermal velocity only
3. C.
   Both drift velocity and thermal velocity
4. D.
   Neither drift nor thermal velocity

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1. A.
   $0.15\, \frac{\mathrm{V}}{\mathrm{m}}$
2. B.
   $0.30\, \frac{\mathrm{V}}{\mathrm{m}}$
3. C.
   $1.5\, \frac{\mathrm{V}}{\mathrm{m}}$
4. D.
   $3.0\, \frac{\mathrm{V}}{\mathrm{m}}$

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1. A.
   only relaxation time '$\tau$' of electrons decreases with temperature.
2. B.
   only number of electrons per unit volume 'n' increases appreciably.
3. C.
   '$\tau$' decreases with temperature but 'n' does not change appreciably.
4. D.
   '$\tau$' decreases with temperature and 'n' increases.

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1. A.
   Mobility increases with increase in applied electric field.
2. B.
   Mobility decreases with increase in temperature.
3. C.
   Mobility is independent of the mass of the charge carrier.
4. D.
   Mobility increases with increase in temperature

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1. A.
   $(P_1 + P_2)$
2. B.
   $\frac{P_1 + P_2}{2}$
3. C.
   $\frac{P_1 P_2}{2(P_1 + P_2)}$
4. D.
   $\frac{P_1 P_2}{4(P_1 + P_2)}$

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1. A.
   Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
2. B.
   Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
3. C.
   Assertion (A) is true, but Reason (R) is false.
4. D.
   Both Assertion (A) and Reason (R) are false.

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1. A.
   Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
2. B.
   Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
3. C.
   Assertion (A) is true, but Reason (R) is false.
4. D.
   Both Assertion (A) and Reason (R) are false.

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1. A.
   Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
2. B.
   Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
3. C.
   Assertion (A) is true, but Reason (R) is false.
4. D.
   Assertion (A) is false and Reason (R) is also false.

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1. A.
   A straight line through the origin over the whole range of V.
2. B.
   A curve rising steeply from the origin which then flattens and turns slightly downward at large V.
3. C.
   A line straight near the origin which then bends away below its own dashed straight-line extension.
4. D.
   A line straight near the origin which then bends away above its own dashed straight-line extension.

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1. A.
   due to error in voltmeter reading only.
2. B.
   due to error in ammeter reading only.
3. C.
   equal to the sum of error in voltmeter reading and error in ammeter reading.
4. D.
   equal to error in voltmeter reading divided by the error in ammeter reading.

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1. A.
   reading in ammeter decreases and reading in voltmeter increases.
2. B.
   readings in both voltmeter and ammeter increase.
3. C.
   reading in ammeter increases and reading in voltmeter decreases.
4. D.
   readings in both voltmeter and ammeter decrease.

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1. A.
   $v_1 > v_2 > v_3$
2. B.
   $v_2 > v_3 > v_1$
3. C.
   $v_3 > v_2 > v_1$
4. D.
   $v_1 = v_2 = v_3$

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1. A.
   $E_1 = E_2 = E_3$
2. B.
   $E_3 > E_2 > E_1$
3. C.
   $E_2 > E_3 > E_1$
4. D.
   $E_1 > E_2 > E_3$

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1. A.
   $\dfrac{P}{4}$
2. B.
   $\dfrac{P}{2}$
3. C.
   P
4. D.
   2P

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1. A.
   $\dfrac{1}{4}$
2. B.
   $\dfrac{1}{2}$
3. C.
   1
4. D.
   2

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1. A.
   $T_2 = 2T_1$
2. B.
   $T_1 > T_2$
3. C.
   $T_1 = T_2 / 3$
4. D.
   $T_1 < T_2$

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1. A.
   $\left(\dfrac{n^2 - 1}{n^2}\right)R$
2. B.
   $\left(\dfrac{n^2 + 1}{n^2 - 1}\right)R$
3. C.
   $\left(\dfrac{n^2 - 1}{n}\right)R$
4. D.
   $\dfrac{(n^2 + 1)\,R}{n^2}$

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1. A.
   $6\,\Omega$
2. B.
   $\dfrac{8}{3}\,\Omega$
3. C.
   $\dfrac{16}{3}\,\Omega$
4. D.
   $2\,\Omega$

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1. A.
   12.0 V, 2.0 A
2. B.
   2.0 V, 0.5 A
3. C.
   6.0 V, 2.0 A
4. D.
   12 V, 0.5 A

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1. A.
   R
2. B.
   $\frac{R}{2}$
3. C.
   $\frac{R}{8}$
4. D.
   2R

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1. A.
   $R_A > R_B > R_C$
2. B.
   $R_B > R_C > R_A$
3. C.
   $R_C > R_A > R_B$
4. D.
   $R_A > R_C > R_B$

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1. A.
   the electrons coming from the power source move fast through the initially empty filament.
2. B.
   the filament may be old having low resistance.
3. C.
   electric field is established instantaneously across the filament which pushes the electrons.
4. D.
   free electrons in the filament travel with the speed of light.

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1. A.
   $R$
2. B.
   $R^2$
3. C.
   $R^3$
4. D.
   $R^4$

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1. A.
   all the three resistors in series.
2. B.
   all the three resistors in parallel.
3. C.
   two resistors in series and then this combination in parallel with the third resistor.
4. D.
   two resistors in parallel and then this combination in series with the third resistor.

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1. A.
   1.05
2. B.
   1
3. C.
   0.95
4. D.
   1.1

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1. A.
   2
2. B.
   $\frac{1}{2}$
3. C.
   $\frac{3}{2}$
4. D.
   $\frac{8}{9}$

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1. A.
   Using a wire of same radius and twice the length
2. B.
   Using a wire of same radius and half length
3. C.
   Using a wire of same length and twice the radius
4. D.
   Using a wire of same length and half the radius

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1. A.
   4R
2. B.
   $\infty$
3. C.
   $\dfrac{R}{4}$
4. D.
   $\dfrac{4R}{3}$

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1. A.
   $1{\cdot}0^{\circ}$C
2. B.
   $1{\cdot}5^{\circ}$C
3. C.
   $2{\cdot}0^{\circ}$C
4. D.
   $4{\cdot}0^{\circ}$C

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1. A.
   $\dfrac{1}{2}$
2. B.
   $\dfrac{1}{4}$
3. C.
   2
4. D.
   1

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1. A.
   $2{\cdot}5 \times 10^{4}$
2. B.
   $3{\cdot}0 \times 10^{5}$
3. C.
   $3{\cdot}75 \times 10^{6}$
4. D.
   $5{\cdot}0 \times 10^{7}$

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1. A.
   $250\,^{\circ}\mathrm{C}$
2. B.
   $500\,^{\circ}\mathrm{C}$
3. C.
   $850\,^{\circ}\mathrm{C}$
4. D.
   $1000\,^{\circ}\mathrm{C}$

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1. A.
   I decreases and II increases.
2. B.
   I increases and II is almost constant.
3. C.
   Both I and II increase.
4. D.
   I decreases and II is almost constant.

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1. A.
   II and III change, but I is constant.
2. B.
   I and II change, but III is constant.
3. C.
   I and III change, but II is constant.
4. D.
   All I, II and III change.

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1. A.
   $2\ \Omega$
2. B.
   $1.2\ \Omega$
3. C.
   $1\ \Omega$
4. D.
   $0.5\ \Omega$

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1. A.
   P
2. B.
   $\frac{P}{2}$
3. C.
   $\frac{P}{4}$
4. D.
   2P

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1. A.
   A will increase, V will decrease.
2. B.
   A will decrease, V will increase.
3. C.
   Both A and V will decrease.
4. D.
   Both A and V will increase.

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1. A.
   $\dfrac{v_d}{2}$
2. B.
   $v_d$
3. C.
   $2\,v_d$
4. D.
   $4\,v_d$

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1. A.
   6 V
2. B.
   8 V
3. C.
   9 V
4. D.
   12 V

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