Question

In the figure, voltmeter and ammeter shown are ideal. Then voltmeter and ammeter readings, respectively, are

Answer 1

Since, both ammeter and voltmeter are ideal, so distribution of potential will be as shown below.


The given circuit can be redrawn as below:

Resistors $20\Omega$, $100\Omega$ and $25\Omega$ are in parallel, so their equivalent resistance,

$\frac{1}{R_{eqv}}=\frac{1}{20}+\frac{1}{100}+\frac{1}{25}$

$R_{eqv}=10\Omega$

Now, the circuit is redrawn as,


Current through the circuit,

$I=\frac{200}{5+10+5}=10\text{A}$

So, the potential difference across $10\Omega$ will be the reading of voltmeter.

$V=10I=10\times 10=100\text{V}$

This will be the voltmeter reading.

Also, this will be the p.d. across each of $20\Omega ,100\Omega$ and $25\Omega$ resistors.

Ammeter reading = current through $25\Omega$ resistor

$I_{25\Omega }=\frac{100}{25}=4\text{A}$

Hence, $\left(\text{B}\right)$ is the correct answer.