Moving Charges And Magnetism Ques 2
2. Current sensitivity of a moving coil galvanometer is $5$ $ \mathrm{div} / \mathrm{mA}$ and its voltage sensitivity (angular deflection per unit voltage applied) is $20 $ $\mathrm{div} / \mathrm{V}$. The resistance of the galvanometer is
[2018]
(a) $40 $ $\Omega$
(b) $25 $ $\Omega$
(c) $500 $ $\Omega$
(d) $250$ $ \Omega$
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Answer:
Correct Answer: 2.(d)
Solution: (d) Current sensitivity of moving coil galvanometer
$ \mathrm{I}_{\mathrm{s}}=\frac{N B A}{C} $ $\quad$ ……..(i)
Voltage sensitivity of moving coil galvanometer,
$ \mathrm{V}_{\mathrm{s}}=\frac{N B A}{C R_G} $ $\quad$ ……..(ii)
Dividing eqn. (i) by (ii)
Resistance of galvanometer
$ \mathrm{R}_{\mathrm{G}}=\frac{I_s}{V_s}=\frac{5 \times 1}{20 \times 10^{-3}}=\frac{5000}{20}=250 $ $\Omega $
BETA
