Question

An ammeter and a voltmeter of resistance $R$ are connected in series to an electric cell of negligible internal resistance. This reading are $A$ and $V$ respectively. If another resistance $R$ is connected in parallel with the voltmeter, then

• A. Both $A$ and $V$ will increase
• B. Both $A$ and $V$ will decrease
• C. $A$ will decrease and $V$ will increase
• D. $A$ will increase and $V$ will decrease

Answer 1

Answer: (D)

$A$ will increase and $V$ will decrease

The effective resistance will decrease when resistance $R$ is connected in parallel with the voltmeter.
According to Ohm's law, $V=IR$ or, $R=\frac{V}{I}$
Here, as $R$ decreases, so $V$ decrease and $I$ should increase.