Question

A cell of e.m.f. 2 V and negotiable internal resistance is connected to resistors $R_1$ and $R_2$ as shown in the figure. The resistance of the voltmeter, $R_1$ and $R_2$ are $80\Omega ,40\Omega$ and $80\Omega$ respectively. The reading of the voltmeter is :-

• A. 1.78 V
• B. 1.60 V
• C. 0.80 V
• D. 1.33 V

Answer 1

The correct option is C 0.80 V

resistance of series combination=80+40+80=200$\Omega$

internal resistance =0

circuit resistance=200$\Omega$ and e.m.f =2v

current through the circuit $I=\frac{V}{R}=\frac{2}{200}=0.01A$

$V=0.01\times 80=0.8$V