Question

In the experiment to determine the galvanometer resistance by half-deflection method, the plot of \(\frac{1}{ \theta}\) vs the resistance (R) of the resistance box is shown in the figure. The figure of merit of the galvanometer is .............. ×10^–1 A/division. [The source has emf 2V]

Answer 1

Correct Answer: 5

Using the equation:

\[ i = K\theta, \]

At half deflection:

\[ \frac{2}{G + R} = K\theta. \]

Rearranging:

\[ \frac{1}{\theta} = \frac{(G + R)K}{2} = RK + \frac{GK}{2}. \]

From the slope of the graph:

\[ \text{Slope} = K = 0.5 = 5 \times 10^{-1} \, \text{A/division}. \]