A coil heating a bucket full of water raises the temperature by 5 C in 2 min. lf the current in the coil is doubled, what will be the change in the temperature of water in 1 min? (Assume no loss of heat to the surroundings)
1. | 10 °C | 2. | 5 °C |
3. | 20 °C | 4. | 15 °C |
If the potential difference across ends of a metallic wire is doubled, the drift velocity of charge carriers will become:
1. double
2. half
3. four times
4. one-fourth
Potentiometer wire is replaced by another wire of the same material and same length but half the radius. For a given potential difference, sensitivity of the potentiometer:
1. decreases.
2. increases.
3. remains the same.
4. may increase or decrease.
The resistance between terminals A and B is:
1. 5
2. 15
3. 10
4. 20
What is the ratio of currents flowing in the resistors x and y of resistance 10 each?
1. 1
2. 0.5
3. 1.5
4. 2.0
What is the equivalent resistance between points a and b, if the value of each resistance is R?
1. | 7R | 2. | 5R |
3. | 4R | 4. | 3R |
What is the value of current I in the network shown below?
1. | 2 A | 2. | 3 A |
3. | 4 A | 4. | 7 A |
A current passes through a wire of variable cross-section in steady-state as shown. Then incorrect statement is:
1. | Current density increases in the direction of the current. |
2. | Potential increases in the direction of the current. |
3. | Electric field increases in the direction of the current. |
4. | Drift speed increases in the direction of the current. |
The value of E (emf of the cell) in the circuit given below is:
1. | 24 V | 2. | 32 V |
3. | 16 V | 4. | 8 V |
Two cells of e.m.f. E and internal resistance r1 and r2 are connected in series through an external resistance R. The value of R for which the potential difference across one of the cells becomes zero will be:
1.
2.
3.
4.