1.

A voltmeter has a resistance of 100Ω. What will be its reading when it is connected across a cell of e.m.f. 2 V and internal resistance 20Ω?

Answer»

Given: R = 100Ω, r = 20, E = 2 V

To find: Reading of voltmeter (V)

Formula: V = E - Ir

Calculation: Current through the circuit is given by

I = \(\frac{E}{R+r}=\frac{2}{100+20}=\frac{2}{120}\)

∴ I = \(\frac{1}{60} A\)

From formula,

V = 2 - (\(\frac{1}{60} \times20\)) =2 - 0.3333

∴ V = 1.667 V 

Ans: The reading on the voltmeter is 1.667 V.



Discussion

No Comment Found

Related InterviewSolutions