1. | \(28\) C | 2. | \(30.5\) C |
3. | \(8\) C | 4. | \(82\) C |
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 temperature coefficient of resistance for a wire is 0.00125/°C. At 300K its resistance is 1 ohm. The temperature at which the resistance becomes 2 ohm is
1. 1154 K
2. 1100 K
3. 1400 K
4. 1127 K
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 \(v_d\) varies with the intensity of the electric field as per the relation:
1. \(v_{d} \propto E\)
2. \(v_{d} \propto \frac{1}{E}\)
3. \(v_{d}= \text{constant}\)
4. \(v_{d} \propto E^2\)
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.
2.
3.
4.
When a piece of aluminum wire of finite length is drawn through a series of dies to reduce its diameter to half its original value, its resistance will become :
1. Two times
2. Four times
3. Eight times
4. Sixteen times
Through a semiconductor, an electric current is due to drift off:
1. Free electrons
2. Free electrons and holes
3. Positive and negative ions
4. Protons