A galvanometer of resistance 25 Ω shows a deflection of 5 divisions when a current of 2 mA is passed through it. If a shunt of 4 Ω is connected and there are 20 divisions on the scale, then the range of the galvanometer is

• 1 A

• 58 A

• 58 mA

• 30 mA

The length of a given cylindrical wire is increased by 150%. Due to the consequent decrease in diameter the change in the resistance of the wire will be

• 200 %

• 525 %

• 300 %

• 400 %

The measurement of voltmeter in the following circuit is

• 2.25 V

• 4.25 V

• 2.75 V

• 6.25 V

A meter bridge is set-up as shown, to determine an unknown resistance X using a standard 10 ohm resistor. The galvanometer shows null point when tapping-key is at 52 cm mark. The end-corrections are 1 cm and 2 cm respectively for the ends A and B. The determined value of

• 10.2 ohm

• 10.6 ohm

• 10.8 ohm

• 11.1 ohm

A and B are two points on a uniform ring of resistance R. The ∠ ACB = 0, where C is the centre of the ring. The equivalent resistance between A and B is

In the circuit shown in figure, if A the diode forward voltage is 0.3 V, the voltage difference between A and B is

• 1.3 V

• 2.3 V

• 0

• 0.5 V

307.

Assertion:  An electrical bulb starts glowing instantly as it is switched on. 

Reason:  Drift speed of electrons in a metallic wire is very large.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false

A voltmeter of resistance 20000 Ω reads 5 volt. To make it read 20 volt, the extra resistance required is

• 40000 Ω in parallel

• 60000 Ω in parallel

• 60000 Ω in series

• 40000 Ω in series

Ten identical cells each of potential E and internal resistance r are connected in series to form a closed circuit. An ideal voltmeter connected across three cells, will read

• 10 E

• 3 E

• 13 E

• 7 E

A steady current flows in a metallic conductor of non-uniform cross-section. Which of these quantities is constant along the conductor?

• Electric field

• Drift velocity

• Current

• Current density