Question

In the circuit shown the current through the $4\Omega$ resistor is $1$ amp when the points $P$ and $M$ are connected to a d.c voltage source. The potential difference between the points $M$ and $N$ is:

• A. $0.5$ volt
• B. $3.2$ volt
• C. $1.5$ volt
• D. $1.0$ volt

Answer 1

The correct option is B $3.2$ volt

In the given fig$:-$

In parallel resistances$,$ the potential differences across them is same$.$

potential difference across $PM$

$V=4\times 1=4volt\left(i.e,across4\Omega \right)$

Equivalent resistance of lower side arm$,$

$R_{eq}=1+\frac{0.5\times 0.5}{0.5+0.5}=1.25\Omega$

Let current $I$ flow in lower branch$,$

So$,$ $1.25I=4V$

$I=\frac{4}{1.25}=3.2A$

therefore$,$

$3.2A$ currents flows in $1\Omega$ resistance$,$

hence potential difference between $M$ and $N$ is

$V^{\prime }=3.2\times 1=3.2volt$

Hence,

option $\left(B\right)$ is correct answer.