The drift speed of electrons in copper wire of diameter and length l is v. If the potential difference across the wire is doubled, then the new drift speed becomes
Options
(a) v […]
A steady current of 1.5 amp flows through a copper voltmeter for 10 minutes. If the electrochemical equivalent of copper is 30 x 10⁻⁵ g coulomb⁻¹, the mass of copper deposited on the electrode will […]
Two bulbs 60 W and 100 W designed for voltage 220 V are connected in series across 220 V source. The net power dissipated is
Options
(a) 80W (b) 160W (c) 37.5W (d) […]
The resistance of an ammeter is 13Ω and its scale is graduated for a current upto 100 amps. After an additional shunt has been connected to this ammeter it becomes possible to measure currents upto […]
Three resistances P,Q,R each of 2Ω and an unknown resistances S form the four arms of a Wheatstone bridge circuit. When a resistance of 6Ω is connected in parallel to S the bridge gets balanced. […]
Which one of the following electrical meter has the smallest resistance?
Options
(a) Ammeter (b) Milliammeter (c) Galvanometer (d) Voltmeter
Correct Answer:
Ammeter
Explanation:
A milliammeter will have greater resistance than ammeter because,
1. […]
A steady current is passing through a linear conductor of non-uniform cross-section. The net quantity of charge crossing any cross-section per second is
Options
(a) independent of area of cross-section (b) directly proportional […]
Heat produced in a resistance according to which law?
Options
(a) Thomson’s law of heating (b) Faraday’s law (c) Joule’s law of heating (d) Ohm’s law
Correct Answer:
Joule’s law of heating
Explanation:
According […]
Masses of three wires of copper are in the ratio of 1:3:5 and their lengths are in the ratio of 5:3:1. The ratio of their electrical resistances is
Options
(a) (1:3:5) (b) (5:3:1) […]
Copper and carbon wires are connected in series and the combined resistor is kept at 0⁰C. Assuming the combined resistance does not vary with temperature, the ratio of the resistances of carbon and copper wires […]
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