Current Electri...

The resistivity of a potentiometer wire is 40 × 10^–8 ohm m and its area of cross-section is 8 × 10^–6m². If 0.2 amp current is flowing through the wire, the potential gradient will be

Potentiometer wire of length 1 m is connected in series with 490 Ω resistance and 2 V battery. If 0.2 mV /cm is the potential gradient, then resistance of the potentiometer wire is

The resistance of an ideal voltmeter is

A 100 V voltmeter of internal resistance 20 kΩ in series with a high resistance R is connected to a 110 V line. The voltmeter reads 5 V, the value of R is

Constantan wire is used in making standard resistances because its

The net resistance of a voltmeter should be large to ensure that

In the circuit shown P ≠ R, the reading of the galvanometer is same with switch S open or closed. Then

In the following Wheatstone bridge P/Q = R/S . If key K is closed, then the galvanometer will show deflection

If resistance of voltmeter is 10000 Ω and resistance of ammeter is 2 Ω, then find R when voltmeter reads 12V and ammeter reads 0.1 A

Two resistances are connected in two gaps of a metre bridge. The balance point is 20 cm from the zero end. A resistance of 15 ohms is connected in series with the smaller of the two. The null point shifts to 40 cm. The value of the smaller resistance in ohms is