The deflection in a moving coil galvanometer is

$A$ galvanometer of resistance $50 \ \Omega$ is connected to a battery of $8 \ V$ along with a resistance of $3950 \ \Omega$ in series. $A$ full-scale deflection of $30$ divisions is obtained in the galvanometer. In order to reduce this deflection to $15$ divisions,the resistance in series should be . . . . . . $\Omega$.

When a galvanometer is shunted with a $4\,\Omega$ resistance,the deflection is reduced to one-fifth. If the galvanometer is further shunted with a $2\,\Omega$ wire,the further reduction in the deflection will be (the main current remains same).

Explain the solution to the difficulties that arise when using a galvanometer directly as an ammeter.

$A$ student connects a voltmeter,an ammeter,and a resistor as shown in the circuit. If the voltmeter reading is $20 \ V$ and the ammeter reading is $4 \ A$,then the resistance $R$ will be:

The deflection in a moving coil galvanometer falls from $25$ divisions to $5$ divisions when a shunt of $24\ \Omega$ is applied. The resistance of the galvanometer coil will be: (in $\Omega$)