The length of a potentiometer wire is and it carries a current of

PHYSICS · Single correct · CBSE · Physics · Current Electricity · Current Electricity

Problem

The length of a potentiometer wire is

600\text{ cm}

and it carries a current of

40\text{ mA}

. For a cell of emf

2\text{ V}

and internal resistance

10\,\Omega

, the null point is found at

500\text{ cm}

. On connecting a voltmeter across the cell, the balancing length decreases by

10\text{ cm}

. The voltmeter reading is (a)

1.96\text{ V}

(b)

1.8\text{ V}

(c)

1.64\text{ V}

(d)

0.96\text{ V}