Multiple Choice QuestionsA 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 %
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
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
