Question

In the circuit shown, the cell of emf $6V$ is ideal. The resistor in which the power dissipated is greatest, is

• A. $5\Omega$
• B. $3\Omega$
• C. $9\Omega$
• D. $18\Omega$

Answer 1

Answer: (A)

The circuit can be drawn as

As $6\Omega$ an $3\Omega$ are in parallel

As $18\Omega$ and $9\Omega$ are in parallel. Also both $2\Omega$ are in parallel
At point $P$ potential is equally divided as resistance of both parts are same $(6\Omega )$ .
Equivalent resistance ( $R_{eq}$ ) of the circuit is $12\Omega$ .
Current through the battery $I=\frac{V}{R_{eq}}=\frac{6}{12}=\frac{1}{2}A$
So power in $5\Omega$ is maximum