WAEC - Physics (1995 - No. 53)
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
解释
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.