A moving-coil meter with an internal resistance of 100 Ω has a full-scale deflection when a current of 10 mA flows through it. What value of resistance would convert it to read 10 V at full-scale deflection?
- 20
- 100
- 600
-
900
- 1000
The correct answer is: D
Explanation
Galvanometer resistance = 100Ω; Voltmeter reading = 10V, Current at full scale deflection \(I_g\) = 10mA = 0.01A
Value of resistance = \(\frac{V}{I_g}\) - r
= \(\frac{10}{0.01}\) - 100 = 1000 - 100 = 900Ω.