Question 415: Current Electricity

Question

As shown in the figure, the voltmeter reads $$2 \mathrm{~V}$$ across $$5 ~\Omega$$ resistor. The resistance of the voltmeter is _________ $$\Omega$$.

Accepted Answer

$$
i_1=\frac{2 V}{5 \Omega}=\frac{2}{5} \mathrm{~A}
$$
$$
i=\frac{1 V}{2 \Omega}=\frac{1}{2} A
$$
$	herefore$ Current through voltmeter $=i-i_1$
$$
=\frac{1}{2}-\frac{2}{5}=\frac{5-4}{10}=\frac{1}{10} \mathrm{~A}
$$
$	herefore$ For voltmeter
$$
2=\left(\frac{1}{10}ight) R \Rightarrow R=20 \Omega
$$

Current Electricity

As shown in the figure, the voltmeter reads $2 \mathrm{~V} across 5 ~\Omega resistor. The resistance of the voltmeter is _________ \Omega$.

Choose the correct answer: