question_answer

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 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

Correct Answer: D

Solution :

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