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

Answer

C

Explanation

(c) KEY CONCEPT : Resistance of Galvanometer,
`G = (Current sensitivity)/(Voltage sensitivity) rArr G = 10/2 = 5Omega`
Here `i_g = Full scale deflection current = 150/10 = 15 mA`
V = voltage to be measured = 150 volts
(such that each division reads 1 volt).
`rArr R = 150/(15 xx 10^(-3)) -5 = 9995 Omega`