A moving coil galvanometer has 150 equal divisions. Its current sensitivity is 10-divisions per milliampere and voltage sensitivity is 2 divisions per millivolt. In order that each division reads 1 volt, the resistance in ohms needed to be connected in series with the coil will be -

Options

A. 99995
B. 9995
C. `10^(3)`
D. `10^(5)`

Answer

B

Explanation

(b) `I_(max) = (150)/(10) = 15 mA, V_(max) = (150)/(2) = 75 mV`
resistance of galvanometer: `G = (V_(max))/(I_(max)) = (75)/(15) = 5 Omega`
Now range of voltmeter `= 150 xx 1 = 150 V`
`150 = (5 + R) I_(max) implies R = 9995 Omega`