Given below are two statements:Statement I: I | vedclass

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(D) For a moving coil galvanometer,the torque is given by $	au = NIAB \sin 	heta = k \phi$,where $N$ is the number of turns,$I$ is the current,$A$ i

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Statement $I$ is true but Statement $II$ is false.

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(D) For a moving coil galvanometer,the torque is given by $	au = NIAB \sin 	heta = k \phi$,where $N$ is the number of turns,$I$ is the current,$A$ is the area,$B$ is the magnetic field,and $k$ is the torsional constant.The current sensitivity is defined as $S_i = \frac{\phi}{I} = \frac{NBA}{k}$.If $N$ is doubled,$S_i$ becomes $2 	imes \frac{NBA}{k}$,so Statement $I$ is true.The voltage sensitivity is defined as $S_v = \frac{\phi}{V} = \frac{\phi}{IR} = \frac{S_i}{R} = \frac{NBA}{kR}$.When the number of turns $N$ is doubled,the length of the wire in the coil also doubles,which means the resistance $R$ of the coil also doubles $(R \propto N)$.Therefore,$S_v = \frac{(2N)BA}{k(2R)} = \frac{NBA}{kR}$.Since $S_v$ remains unchanged,Statement $II$ is false.

$S. No.$	Resistance $R \ (\Omega)$	Deflection $(\theta)$	Shunt $S \ (\Omega)$	Half deflection $(\theta / 2)$	Galvanometer resistance $(G)$
$1$	$3300$	$30$	$80$	$15$	$G_1$
$2$	$5000$	$20$	$80$	$10$	$G_2$

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