Two moving coil galvanometers M1 and M2 have the following particulars: $N_1=30$, $A_1=3.6 imes 10

Question

Two moving coil galvanometers M1 and M2 have the following particulars: $N_1=30$, $A_1=3.6 	imes 10^{-3}	ext{ m}^2$, $B_1=0.25	ext{ T}$ and $N_2=42$, $A_2=1.8 	imes 10^{-3}	ext{ m}^2$, $B_2=0.50	ext{ T}$. The spring constants are identical. Their resistances are $R_1=10\ \Omega$ and $R_2=14\ \Omega$. The ratio of voltage sensitivity of M2 to M1 is:

Professor PC Thomas Classes · Answer

Voltage sensitivity $V_s = \frac{I_s}{R}$. Ratio $\frac{V_{s2}}{V_{s1}} = \frac{I_{s2}/R_2}{I_{s1}/R_1} = \frac{1.4 	imes 10}{14} = 1$.