Question

A moving coil galvanometer A has $100$ turns and resistance $10\Omega$. Another galvanometer B has $50$ turns and resistance $5\Omega$. The other quantities are same in both the cases. Then the voltage sensitivity of

• A. A is greater than that of B
• B. B is greater than that of A
• C. A and B is Same
• D. cannot be compared

Answer 1

The correct option is C A and B is Same

Number of turns in coil A $N_A=100$

Resistance of coil A $R_A=10\Omega$

Number of turns in coil B $N_B=50$

Resistance of coil B $R_B=5\Omega$

Voltage sensitivity of moving coil galvanometer $V_s=\frac{NBA}{KR}$

$\therefore$ $V_s\propto \frac{N}{R}$ (keeping all other quantities to be same)

For coil A : $\frac{N_A}{R_A}=\frac{100}{10}=10$

For coil B : $\frac{N_B}{R_B}=\frac{50}{5}=10$

$⟹$ $V_{s_A}=V_{s_B}$

Thus both have same voltage sensivity.