$A$ moving coil galvanometer has $48$ turns and the area of the coil is $4 \times 10^{-2} \, m^2$. If the magnetic field is $0.2 \, T$,then to increase the current sensitivity by $25\%$ without changing the area $(A)$ and the magnetic field $(B)$,the number of turns should become:

$A$ galvanometer having $30$ divisions has a current sensitivity of $0.0625 \frac{\text{div}}{\mu A}$. If it is converted into a voltmeter to read a maximum of $6 \text{ V}$,then the resistance of that voltmeter is:

$A$ moving coil galvanometer is converted into an ammeter reading up to $0.03\,A$ by connecting a shunt of resistance $4r$ across it,and into an ammeter reading up to $0.06\,A$ when a shunt of resistance $r$ is connected across it. What is the maximum current which can be sent through this galvanometer if no shunt is used?

An ammeter with a resistance of $0.018 \, \Omega$ can measure $1 \, A$. What shunt resistance is required to enable it to measure $10 \, A$?

When a galvanometer is shunted by a resistance $S$, its current capacity increases $n$ times. If the same galvanometer is shunted by another resistance $S'$, its current capacity will increase to $n'$. The value of $n$ in terms of $n'$, $S$, and $S'$ is

Two moving coil meters $M_1$ and $M_2$ have the following particulars:
$R_1 = 10\,\Omega, N_1 = 30, A_1 = 3.6 \times 10^{-3}\, m^2, B_1 = 0.25\, T$
$R_2 = 14\,\Omega, N_2 = 42, A_2 = 1.8 \times 10^{-3}\, m^2, B_2 = 0.50\, T$
(The spring constants are identical for the two meters). Determine the ratio of voltage sensitivity of $M_2$ and $M_1$.