Physics Question from JEE Main 2025 · 2 April, Shift 2

In a moving coil galvanometer, two moving coils $M_1$ and $M_2$ have the following particulars: $R_1 = 5 \, \Omega$, $N_1 = 15$, $A_1 = 3.6 \times 10^{-3} \, m^2$, $B_1 = 0.25 \, T$ $R_2 = 7 \, \Omega$, $N_2 = 21$, $A_2 = 1.8 \times 10^{-3} \, m^2$, $B_2 = 0.50 \, T$

Assuming that torsional constant of the springs are same for both coils, what will be the ratio of voltage sensitivity of $M_1$ and $M_2$?