question_answer

If resistance of voltmeter is 10000W and resistance of ammeter is 2W then find R when voltmeter reads 12V and ammeter reads 0.1 A                                                   [BCECE 2005]

A)         118 W                              

B)         120 W

C)         124 W                              

D)         114W

Correct Answer: A

Solution :

                                         According to following figure Reading of voltmeter = Potential difference between A and B = i (R + 2)Þ 12 = 0.1 (R + 2) Þ R = 118 W.