If there are two bulbs of (\(40~\text{W},200~\text{V}\)), and (\(100~\text{W},200~\text{V}\)), then the correct relation for their resistance is:
1. \(R_{40}<R_{100}\)
2. \(R_{40}>R_{100}\)
3. \(R_{40}=R_{100}\)
4. no relation can be predicted
When three identical bulbs are connected in series, the consumed power is \(10\) W. If they are now connected in parallel then the consumed power will be:
1. \(30\) W
2. \(90\) W
3. \(\frac{10}{3}\) W
4. \(270\) W
According to the Faraday Law of electrolysis, the mass deposited at electrode will be proportional to:
1. m ∝ I2
2. m ∝ Q
3. m ∝ Q2
4. 'm' does not depend on Q
In a hot wire ammeter due to the flowing of the current, the temperature of the wire is increased by \(5^{\circ}\) C. If the value of the current is doubled, then the increase in temperature will be:
1. \(15^{\circ}\) C
2. \(20^{\circ}\) C
3. \(25^{\circ}\) C
4. \(30^{\circ}\) C
The potentiometer is best for measuring voltage, as:
1. It has a sensitive galvanometer
2. It has wire of high resistance
3. It measures p.d. like in closed circuit
4. It measures p.d. like in open circuit
When three identical bulbs of \(60\) watts and \(200\)-volt rating are connected in series to a \(200\)-volt supply, the power drawn by them will be:
1. \(180\) watts
2. \(10\) watts
3. \(20\) watts
4. \(60\) watts
The electric resistance of a particular wire of iron is R. If its length and radius are doubled, then:
1. | The resistance will be halved and the specific resistance will remain unchanged |
2. | The resistance will be halved and the specific resistance will be doubled |
3. | The resistance and the specific resistance, will both remain unchanged |
4. | The resistance will be doubled and the specific resistance will be halved |
Resistances \(n\), each of \(r\) ohm, when connected in parallel give an equivalent resistance of \(R\) ohm. If these resistances were connected in series, the combination would have resistance in ohms, equal to:
1. \(\dfrac{R}{n^2}\)
2. \(\dfrac{R}{n}\)
3. \(nR\)
4. \(n^2R\)
The current in \(8~\Omega\) resistance is (in the figure below):
1. \(0.69\) A
2. \(0.92\) A
3. \(1.30\) A
4. \(1.6\) A
If the power dissipated in \(5~\Omega\) is \(20\) W then the power dissipated in \(4~\Omega\) is:
1. \(4\) W
2. \(6\) W
3. \(10\) W
4. \(20\) W