Q. No.1. \(0.5~\Omega\)
2. \(0.8~\Omega\)
3. \(1.0~\Omega\)
4. \(0.2~\Omega\)
A battery of internal resistance r, when connected across \(2~\Omega\) resistor supplies a current of 4 A. When the battery is connected across a \(5~\Omega\) resistor, it supplies a current of 2 A. The value of r is:
| 1. | \(2~\Omega\) | 2 | \(1~\Omega\) |
| 3. | \(0.5~\Omega\) | 4. | Zero |
A voltmeter of resistance \(660~\Omega\) reads the voltage of a very old cell to be \(1.32\) V while a potentiometer reads its voltage to be \(1.44\) V. The internal resistance of the cell is:
1. \(30~\Omega\)
2. \(60~\Omega\)
3. \(6~\Omega\)
4. \(0.6~\Omega\)
A current of 2 A flows through a 2 resistor when connected across a battery. The same battery supplies a current of 0.5 A when connected across a 9 resistor. The internal resistance of the battery is:
1. 1/3
2. 1/4
3. 1
4. 0.5
For a cell, the terminal potential difference is 2.2 V when the circuit is open and reduces to 1.8 V when the cell is connected to the resistance of R = 5 Ω. The internal resistance of cell (r) is:
1. \(\frac{10}{9}~ \Omega\)
2. \(\frac{9}{10}~ \Omega\)
3. \(\frac{11}{9}~ \Omega\)
4. \(\frac{5}{9}~ \Omega\)
A set of '\(n\)' equal resistors, of value '\(R\)' each, are connected in series to a battery of emf '\(E\)' and internal resistance '\(R\)'. The current drawn is \(I.\) Now, if '\(n\)' resistors are connected in parallel to the same battery, then the current drawn becomes \(10I.\) The value of '\(n\)' is:
| 1. | \(10\) | 2. | \(11\) |
| 3. | \(20\) | 4. | \(9\) |
2. \(-r\) and \(E\)
A battery is charged at a potential of 15 V for 8 hours when the current flowing is 10 A. The battery on discharge supplies a current of 5 A for 15 hours. The mean terminal voltage during discharges is 14 V. The "Watt hour" efficiency of the battery is:
1. 80%
2. 90%
3. 87.5%
4. 82.5%
A battery has e.m.f. 4 V and internal resistance r. When this battery is connected to an external resistance of 2 ohm, a current of 1 ampere flows in the circuit. How much current will flow if the terminals of the battery are connected directly?
| 1. | 1 A | 2. | 2 A |
| 3. | 4 A | 4. | Infinite |
A battery of e.m.f. E and internal resistance r is connected to a variable resistor R as shown below. Which one of the following is true?
| 1. | Potential difference across the terminals of the battery is maximum when R = r. |
| 2. | Power delivered to the resistor is maximum when R = r. |
| 3. | Current in the circuit is maximum when R = r. |
| 4. | Current in the circuit is maximum when R >> r. |
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