A cell having an emf \(\varepsilon\) and internal resistance \(r\) is connected across a variable external resistance \(R\). As the resistance \(R\) is increased, the plot of potential difference \(V\) across \(R\) is given by:
1. | 2. | ||
3. | 4. |
(a) | conservation of the current density vector. |
(b) | conservation of charge. |
(c) | the fact that the momentum with which a charged particle approaches a junction is unchanged (as a vector) as the charged particle leaves the junction. |
(d) | the fact that there is no accumulation of charges at a junction. |
Which of the above statements are correct?
1. | (b) and (c) |
2. | (a) and (c) |
3. | (b) and (d) |
4. | (c) and (d) |
Which of the following \((\text{I-V})\) graphs represents ohmic conductors?
1. | 2. | ||
3. | 4. |
Figure (i) and figure (ii) both are showing the variation of resistivity \((\rho)\) with temperature (T) for some materials. Identify the type of these materials.
1. | conductor and semiconductor |
2. | conductor and Insulator |
3. | insulator and semiconductor |
4. | both are conductors |
Assertion (A): | The fractional error in \(R\) is most affected by that of the smallest resistance in the combination, other things being equal. |
Reason (R): | In parallel, the conductances add. The contribution to the overall error in the conductance is largest for the largest conductance or the smallest resistance. |
1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
3. | (A) is True but (R) is False. |
4. | (A) is False but (R) is True. |
1. | \( {i}_{0}T\) | 2. | \( \dfrac{{i}_{0}T}{2}\) |
3. | \( \dfrac{{i}_{0}T}{3}\) | 4. | \( \dfrac{{i}_{0}T}{\sqrt{2}}\) |
Assertion (A): | Resistance of a conducting metallic wire depends on the voltage applied across it and current passing through it. |
Reason (R): | Ohm's law is also valid for semiconductors. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |
Assertion (A): | When an external resistor of resistance R (connected across a cell of internal resistance r) is varied power consumed by resistance R is maximum when R=r. |
Reason (R): | Power consumed by a resistor of constant resistance R is maximum when the current through it is maximum. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |
(i) | The brightness of bulb \(C\) is the highest. |
(ii) | If \(A\) fails, \(B\) will not glow. |
(iii) | If \(C\) fails, the brightness of bulb \(D\) increases. |
1. | (i) only |
2. | (ii) only |
3. | (i) and (ii) only |
4. | (ii) and (iii) only |