Question

In given circuit, all resistances are of $10 \,\Omega$. Current flowing through ammeter is

• A. 3.6 A
• B. 1.8 A
• C. 2 A
• D. 1 A

Answer 1

Answer: (A)

An equivalent of the given network is as shown in figure.
If $R_{P}$ be the net resistance, then
$\frac{1}{R_{P}}=\frac{1}{10}+\left(\frac{1}{10+10}\right)+\left(\frac{1}{10+10}\right)+\frac{1}{10} $
$=\frac{1}{10}+\frac{1}{20}+\frac{1}{20}+\frac{1}{10}$
$=\frac{6}{20}=\frac{3}{10}$
$\therefore R_{p}=\frac{10}{3} \Omega$
Hence, current flowing through ammeter is
$I=\frac{V}{R_{P}}=\frac{12}{\left(\frac{10}{3}\right)}=3.6 \,A$