Question 355: Current Electricity

Question

In the circuit shown, a four-wire potentiometer
is made of a 400 cm long wire, which extends
between A and B. The resistance per unit length
of the potentiometer wire is r = 0.01 $\Omega $/cm. If
an ideal voltmeter is connected as shown with
jockey J at 50 cm from end A, the expected
reading of the voltmeter will be :-
![](https://imagex.cdn.examgoal.net/18hoxe66ijw97bghe/dc1ffa2f-4b6e-4ebe-89fd-94febf2599fb/a32f1120-820c-11e9-8081-1d558b7f1d26/file-18hoxe66ijw97bghf.png)

Accepted Answer

Resistance of wire AB = 400 ÃÂ 0.01 = 4 $\Omega $
i = ${3 \over 6} = 0.5A$
Now voltmeter reading = i (Resistance of 50 cm
length)
= (0.5 A) (0.01 ÃÂ 50) = 0.25 volt

Answer

0.25 V

Answer

0.20 V

Answer

0.50V

Answer

0.75 V

Current Electricity

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