The resistance of platinum wire at 0°C°C is 22.05 ΩΩ and at 100°C°C it becomes 22.70 ΩΩ. When the wire is heated to a temperature of t°C°C the resistance of wire becomes 24.91ΩΩ. The value of t is
1. 220
2. 440
3. 310
4. 550
The sensitivity of a potentiometer can be increased by
1. increasing the potential gradient
2. decreasing the length of potentiometer wire
3. decreasing the current in the potentiometer wire
4. all of these
In the circuit shown in figure if power dissipated in 9Ω resistor is 144W, then potential difference across 3.6Ω resistor will beIn the circuit shown in figure if power dissipated in 9Ω resistor is 144W, then potential difference across 3.6Ω resistor will be
1. 36V
2. 18V
3. 9V
4. Zero
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][e = 1.6 × 10−19 Coulomb]
1. 6.25 × 1019 6.25 × 1019
2. 6.25 × 1015 6.25 × 1015
3. 6.25 × 1031 6.25 × 1031
4. 6.25 × 1086.25 × 108
The drift velocity of free electrons in a conductor is vv when a current ii is flowing in it. If both the radius and current are doubled, then the drift velocity will be:
1. | vv | 2. | v2v2 |
3. | v4v4 | 4. | v8v8 |
1. | 11 A | 2. | 22 A |
3. | 44 A | 4. | Infinite |
The current II as shown in the circuit will be:
1. | 10 A10 A | 2. | 203 A203 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
If I be the current limit of a fuse wire of length l and radius r, then select the appropriate relation
1. I α l
2. I α r2
3. I α l0
4. I α r0
Which of the following graph correctly represents the variation of mobility (μ) of electrons with applied electric field (E) in a metallic conductor?
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