$A$ moving coil galvanometer has $N$ number of turns in a coil of effective area $A$,and it carries a current $I$. The magnetic field $B$ is radial. The torque acting on the coil is:

$A$ 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:

Two galvanometers $A$ and $B$ require $3\,mA$ and $5\,mA$ respectively to produce the same deflection of $10$ divisions. Then:

$A$ galvanometer of resistance $30 \Omega$ is connected to a battery of emf $2 \text{ V}$ with $1970 \Omega$ resistance in series. $A$ full-scale deflection of $20$ divisions is obtained in the galvanometer. To reduce the deflection to $10$ divisions,the total resistance in series required is: (in $\Omega$)

$A$ galvanometer of resistance $100 \Omega$ gives full scale deflection for a current of $1 \text{ mA}$. It is converted into an ammeter of range $0 - 10 \text{ A}$. The shunt required is: (in $\text{ }\Omega$)

When a resistance of $100 \Omega$ is connected in series with a galvanometer of resistance $G$,its range is $V$. To double its range,a resistance of $1000 \Omega$ is connected in series. The value of $G$ is: (in $\Omega$)