Question

The reading of voltmeter in the circuit shown is

• A. 2.25 V
• B. 3.25 V
• C. 4.25V
• D. 6.25V

Answer 1

Answer: (A)

2.25 V

Answer 2

The correct answer is Option A) 2.25 V

From the figure, the resistance of 60 $\Omega$ of the resistor and resistance 40 $\Omega$ of the voltmeter are in parallel.

Therefore the equivalent resistance of these two resistances in parallel is given by

Req $=\frac{60\times40}{60+40}=\frac{60\times40}{100}=24\,\Omega$

The total current in the circuit is given by,

I $=\frac{6\,V}{\left(40+24\right)\,\Omega}=\frac{6}{64}=\frac{3}{32}\,A$

The voltmeter reads potential differences across the resistance 60 $\Omega$ connected in parallel to it. Therefore using Ohm's law, the potential across the voltmeter is given by

$\therefore\quad$ Voltmeter reading = $I\times R_{eq}$ $=\frac{3}{32}\times24=\frac{9}{4}V=2.25\,V$

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