Current Electricity

JEE Main level, numerical answer, medium

324 of 380

Question 324 of 380

In the experiment to determine the galvanometer resistance by half-deflection method, the plot of 1/θ1 / \theta vs the resistance (R)(\mathrm{R}) of the resistance box is shown in the figure. The figure of merit of the galvanometer is _____ ×10−1 A/\times 10^{-1} \mathrm{~A} / division. [The source has emf 2V]

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Answer: 5

i=Kθ2G+R=Kθ⇒1θ=(G+R)K2=R(K2)+KG2 Slope =K2=14⇒K=0.5=5×10−1A\begin{aligned} & i=K \theta \\ & \frac{2}{G+R}=K \theta \\ & \Rightarrow \frac{1}{\theta}=\frac{(G+R) K}{2}=R\left(\frac{K}{2}\right)+\frac{K G}{2} \\ & \text { Slope }=\frac{K}{2}=\frac{1}{4} \Rightarrow K=0.5=5 \times 10^{-1} A\end{aligned}

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