Question

In the circuit shown, the readings of ammeter and voltmeter are $4A$ and $20V$ respectively. The meters are non ideal, then $R$ is:

• A. $5\Omega$
• B. Less than $5\Omega$
• C. More than $5\Omega$
• D. Between $4\Omega$ and $5\Omega$

Answer 1

The correct option is C More than $5\Omega$

Ammeter gives reading $4A$,

and both ammeter and voltmeter is not ideal,

Thus voltmeter draws extra current say 'x'

So, According to Kirchoff's law the current passing through resistance would

be ${}^{\prime }4-x^{\prime }$

therefore, resistance $R=\frac{20}{(4-x)}$

where $x>0$

So $R>5$