Question

A dc potentiometer is designed to measure 4 V with a slide wire of 800 mm. A standard cell of emf 1.18 V obtains balance at 1200 mm. A test cell is seen to obtain balance at 1360 mm. The emf of the test cell is

• A. 1.04 V
• B. 1.34 V
• C. 1.50 V
• D. 1.70 V

Answer 1

The correct option is B 1.34 V

$\because$ Balance of 1200 mm is corresponding to an emf of 1.18 V

$\therefore$ Balance of 1360 mm is corresponding to an emf of $\frac{1.18}{1200}\times 1360=1.337\simeq 1.34V$