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. The ratio of current sensitivity of M2 to M1 is:

Professor PC Thomas Classes · Answer

Current sensitivity $I_s = \frac{NAB}{k}$. Ratio $\frac{I_{s2}}{I_{s1}} = \frac{N_2 A_2 B_2}{N_1 A_1 B_1} = \frac{42 	imes 1.8 	imes 0.50}{30 	imes 3.6 	imes 0.25} = 1.4$.