A current of 2 A is to be sent through a resistor of \(5 ~\Omega.\) Number of cells required in series, if each has emf 2 V and internal resistance 0.5 , are:
1. 40
2. 30
3. 20
4. 10
A 50 kW dc generator produces a potential difference of 250 V. If the resistance of the transmission line is 1 , what percentage of the original power is lost during transmission?
1. 80%
2. 40%
3. 20%
4. 10%
A potential divider is used to give outputs of 2 V and 3 V from a 5 V source, as shown in the figure.
Which combination of resistances, from the ones given below, give the correct voltages?
1. | \(\mathrm{R}_1=1 \mathrm{k} \Omega, \mathrm{R}_2=1 \mathrm{k} \Omega, \mathrm{R}_3=2 \mathrm{k} \Omega\) |
2. | \(\mathrm{R}_1=2 \mathrm{k} \Omega, \mathrm{R}_2=1 \mathrm{k} \Omega, \mathrm{R}_3=2 \mathrm{k} \Omega\) |
3. | \(\mathrm{R}_1=1 \mathrm{k} \Omega, \mathrm{R}_2=2 \mathrm{k} \Omega, \mathrm{R}_3=2 \mathrm{k} \Omega\) |
4. | \(\mathrm{R}_1=3 \mathrm{k} \Omega, \mathrm{R}_2=2 \mathrm{k} \Omega, \mathrm{R}_3=2 \mathrm{k} \Omega\) |
Three voltmeters are connected as shown.
A potential difference is applied between A and B. On closing the switch S, readings of voltmeter (s):
1. | V1 increases. |
2. | V2 increases. |
3. | V2 & V3 both increases. |
4. | one of V2 & V3 increases and V1 decreases. |
Two batteries, one of emf 18V and internal resistance 2 and the other of emf 12 V and internal resistance 1 are connected as shown. Reading of the voltmeter is:
(if voltmeter is ideal)
1. 14 V
2. 15 V
3. 18 V
4. 30 V
A capacitor \(C\) is charged with the help of a resistance \(R\) as shown in the figure, Variation of \((V_{R}+V_{C})\) with time t is correctly shown in which of the options?
(\(V_{R}\) and \(V_{C}\) are instantaneous potential drops across \(R\) and \(C\) respectively).
1. | 2. | ||
3. | 4. |
Current through the \(2~\Omega\) resistance in the electrical network shown is:
1. | zero | 2. | \(1\) A |
3. | \(3\) A | 4. | \(5\) A |
The dependence of resistivity \((\rho)\) on the temperature \((T)\) of a semiconductor is, roughly, represented by:
1. | 2. | ||
3. | 4. |
What is the reading of the voltmeter of resistance 1200 connected in the following circuit diagram?
1. 2.5 V
2. 5.0 V
3. 7.5 V
4. 40 V
In the given circuit diagram, 3 identical bulbs are connected. If bulb B3 get fused suddenly, how will the brightness of bulbs B1 and B2 change?
1. | Brightness of bulb B1 will increase whereas brightness of bulb B2 will decrease |
2. | Brightness of bulb B2 will increase whereas brightness of bulb B1 will decrease |
3. | Brightness of both bulbs B1 and B2 will increase |
4. | Brightness of bulb B1 will increase whereas brightness of bulb B2 will remain the same |