A moving coil galvanometer has following characteristics. Number of turns of coil=80, Area of coil=`50mm^(2)`, resistance of coil`=20Omega`, flux density of radial field 0.2T, torsional constant of suspension wire`=5xx10^(-9)Nm//rad`. For this moving coil galvanometer, mark the correct statement(s).

Options

A. The angular deflection produced due to a potential difference of 0.01 mV is 0.08 div
B. Current sensitivity of the device is 160 div/mA
C. Voltage sensitivity of the device is 8 div/mV
D. all of the above

Answer

D

Explanation

Current sensitivity can be writtein as
`impliesl_(S)=(theta)/(l)=(BAN)/(k)`
`=(0.2xx50xx10^(-6)xx80)/(5xx10^(-9))d iv//amp`
`=160xx10^(3)d iv//amp`
`=160d i v//mA`
`therefore`Voltage sensitivity
`V_(S)=(theta)/(V)=(BAN)/(kR)=(l_(S))/(R)`
=8 div/mV
For V=0.01 mV lt brgt `theta=8xx0.01=0.8d i v`