A battery consists of a variable number \(n\) of identical cells (having internal resistance \(r\) each) which are connected in series. The terminals of the battery are short-circuited and the current \(I\) is measured. Which of the graphs shows the correct relationship between \(I\) and \(n?\)
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| 3. | 4. |
| Assertion (A): | In a meter bridge experiment null point for an unknown resistance is put inside an enclosure maintained at a higher temperature. The null point can be obtained at the same point as before by increasing the value of the standard resistance. |
| Reason (R): | Resistance of metal increases with an increase in temperature. |
| 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. |
| Statement I: | Kirchhoff’s junction law follows the conservation of charge. |
| Statement II: | Kirchhoff’s loop law follows the conservation of energy. |
| 1. | Both Statement I and Statement II are incorrect. |
| 2. | Statement I is correct but Statement II is incorrect. |
| 3. | Statement I is incorrect and Statement II is correct. |
| 4. | Both Statement I and Statement II are correct. |
Three resistors are connected to a \(20\) V battery with a constant voltage supply. One of the resistors is a variable resistor. The resistance of the variable resistor is gradually increased from \(0~\Omega\) to \(5\) \(\Omega.\)
Which graph correctly represents how the current drawn from the battery varies with the resistance \((R)\) of the variable resistor?
| 1. | ![]() |
2. | ![]() |
| 3. | ![]() |
4. | ![]() |
The dependence of resistivity \((\rho)\) on the temperature \((T)\) of a semiconductor is, roughly, represented by:
| 1. | 2. | ||
| 3. | 4. |
Which of the following graph represents the variation of resistivity () with temperature (\(T\)) for copper?
| 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) |
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. | ![]() |
| Statement I: | The law of conservation of energy is valid in electric circuits. |
| Statement II: | Kirchhoff's junction law is applicable to electric circuits. |
| 1. | Statement I and Statement II are True and Statement I is the correct explanation of Statement II. |
| 2. | Statement I and Statement II are True and Statement I is not the correct explanation of Statement II. |
| 3. | Statement I is True, and Statement II is False. |
| 4. | Statement I is False, and Statement II is True. |
Which of the following \(({I\text-V})\) graphs represents ohmic conductors?
| 1. | ![]() |
2. | ![]() |
| 3. | ![]() |
4. | ![]() |