Question

In the circuit shown, R1 is increased. What happens to the reading of the voltmeter (ideal)?

Answer 1

Given that,

First resistance is increased.

R₁ and R₂ is connected in series.

We need to calculate the equivalent resistance

Using formula of series

$R=R_{1}+R_{2}$

Put the value into the formula

$R=R_{1}+R_{2}$

Now, R and R₃ is connected in parallel and voltmeter and battery is connected in parallel.

We know that,

When anything is connected in parallel then the voltage will be same in everything.

We need to find what happen to the reading of the voltmeter

According to figure,

The voltmeter is connected in parallel with the battery.

So, there will be no effect on the reading of the voltmeter.

Hence, The reading of the voltmeter will be equal to the emf of the battery.