Question

Four identical resistors of $4\Omega$ each are joined in circuit as shown in figure. The cell $B$ has emf $2V$ and its internal resistance is negligible. The ammeter reading is

• A. $\frac{3}{8}A$
• B. $2A$
• C. $\frac{1}{2}$ A
• D. $\frac{1}{8}A$

Answer 1

Answer: (A)

Here three resistances of $4\Omega$ each are connected in parallel so that their combined resistance $=\frac{4}{3}\Omega$.
It is in series with ammeter, battery and last $4\Omega$ resistance.
$\therefore$ Net resistance $R=\frac{4}{3}+4=\frac{16}{3}\Omega$
$\therefore$ Current in main circuit $=$ ammeter reading,
$i=\frac{E}{R}=\frac{2V}{\frac{16}{3}\Omega }=\frac{3}{8}A$