question_answer

An ammeter and a voltmeter of resistance R are connected in series to an electric cell of negligible internal resistance. Their 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

Correct Answer: D

Solution :

 When resistance R is connected in parallel with the voltmeter, the resistance will decrease. According to Ohm?s law,                         V = lR                         \[r=\frac{6\times {{10}^{7}}}{1.7\times {{10}^{11}}\times 1.5\times {{10}^{-2}}}\] Here, R decrease, so V should decrease and l should increase.