Question

An ammeter and a voltmeter of resistance $R$ are connected in series to an electric cell of negligible internal resistance. Their readings are $A$ and $V$ respectively. If another resistances 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)

When resistance $R$ is connected in parallel with the voltmeter. The effective resistance will decrease. According to Ohm's law

$ V =I R $
or $R =\frac{V}{I} $
Here, $R$ decreases so $V$ should decrease and $I$ should increase.