AB is a potentiometer wire of length 100cm and its resistance is 10ohm. It is connected in series with a resistance R=40 ohm and a battery of e.m.f. wV and negigible internal resistance. If a source of unknown e.m.f. E is balanced by 40cm length of the potentiometer wire, the value of E is:

Options

A. 0.8V
B. 1.6V
C. 0.08V
D. 0.16V

Answer

C

Explanation

As `ma_(cm) = f rArr a_(cm) = (f)/(2m) " so " s_(cm) = (1)/(2) at^(2) = ((f)/(4m))t^(2)`