Question

To use the milliammeter of the previous question as a voltmeter of range 10 V, a resistance R is placed in series with it. The value of R is 

(a) 9 Ω

(b) 99 Ω 

(c) 999 Ω 

(d) 1000 Ω

Answer 1

Correct Answer is: (c) 999 Ω 

i_g = 0.01 A r = 1 Ω V = 10 V

V = (r + R)i_g

R = V / i_g - r = 10 V/ 0.01 A  - 1 Ω = 999 Ω.