Question

Current sensitivity of a moving coil galvanometer is 5 div/mA and its voltage sensitivity (angular deflection per unit voltage applied) is 20 div/V. The resistance of the galvanometer is

• A. 40Ω
• B. 250Ω
• C. 25Ω
• D. 500Ω

Answer 1

The Correct Option is B

To find the resistance of the moving coil galvanometer, we relate current sensitivity and voltage sensitivity.

Given:

• \( S_c = 5\,\text{div/mA} \)
• \( S_v = 20\,\text{div/V} \)

Relation between sensitivities and resistance:

\[ S_v = \frac{S_c}{R} \]

Rearranging:

\[ R = \frac{S_c}{S_v} \]

Substitute values (convert mA to A):

\[ R = \frac{5 \times 10^3}{20} \]

\[ R = 250\,\Omega \]

Final Answer: \( 250\,\Omega \)