Question

In the circuit shown, the current through 8 ohm is same before and after connecting $\epsilon$. The value of $\epsilon$ is

• A. 12 V
• B. 6 V
• C. 4 V
• D. 8 V

Answer 1

Answer: (C)

Before connecting $\epsilon$, the circuit diagram is as shown in the figure.

The equivalent resistance of the given circuit is
$R_{eq}=6\Omega +8\Omega +10\Omega =24\Omega$
Current in the circuit, $I=\frac{12V}{24\Omega }=\frac{1}{2}A$
Before connecting $\epsilon$, the current through $8\Omega$ is
$I=\frac{1}{2}A$
After connecting $\epsilon$, the current through $8\Omega$ is also
$I=\frac{1}{2}A;$
$\therefore \epsilon =\frac{1}{2}A\times 8\Omega =4V$