A current of 1 mA is flowing through a copper wire. How many electrons will pass a given point in one second [e = 1.6 × 10-19 Coulomb]
1. 6.25 × 1019
2. 6.25 × 1015
3. 6.25 × 1031
4. 6.25 × 108
The drift velocity of free electrons in a conductor is v when a current i is flowing in it. If both the radius and current are doubled, then the drift velocity will be:
1. | v | 2. | v2 |
3. | v4 | 4. | v8 |
1. | 1 A | 2. | 2 A |
3. | 4 A | 4. | Infinite |
The current I as shown in the circuit will be:
1. | 10 A | 2. | 203 A |
3. | 23 A | 4. | 53 A |
A meter bridge is set up to determine unknown resistance x using a standard 10 Ω resistor. The galvanometer shows the null point when the tapping key is at a 52 cm mark. End corrections are 1 cm and 2 cm respectively for end A and B. Then the value of x is:
1. 10.2 Ω
2. 10.6 Ω
3. 10.8 Ω
4. 11.1 Ω
The resistivity of iron is 1 × 10–7 ohm – m. The resistance of iron wire of particular length and thickness is 1 ohm. If the length and the diameter of wire both are doubled, then the resistivity in ohm – m will be :
1. 1 × 10–7
2. 2 × 10–7
3. 4 × 10–7
4. 8 × 10–7
The resistivity of a wire :
1. | Increases with the length of the wire |
2. | Decreases with the area of cross-section |
3. | Decreases with the length and increases with the cross-section of the wire |
4. | None of the above statement is correct |
Drift velocity vd varies with the intensity of the electric field as per the relation:
1. vd∝E
2. vd∝1E
3. vd=constant
4. vd∝E2
In a conductor 4 coulombs of charge flows for 2 seconds. The value of electric current will be :
1. 4 volts
2. 4 amperes
3. 2 amperes
4. 2 volts
The specific resistance of a wire is ρ, its volume is 3 m3 and its resistance is 3 ohms, then its length will be
1. √1ρ
2. 3√ρ
3. 1ρ√3
4. ρ√13