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 \(n?\)
1. | |
2. | |
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 supply. One of the resistors is a variable resistor. The resistance of the variable resistor is gradually increased from zero to \(5\) \(\Omega.\)
Which graph shows how the current 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. |
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 |