If only $2\%$ of the main current is to be passed through a galvanometer of resistance $G$,then the resistance of the shunt will be

$A$ 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?

The voltmeter has a range of $10 \ V$ and its internal resistance is $50 \ \Omega$. To increase the range of the voltmeter to $15 \ V$,the resistance which is to be connected is:

$A$ $50\,\Omega$ resistance is connected to a battery of $5\,V$. $A$ galvanometer of resistance $100\,\Omega$ is to be used as an ammeter to measure current through the resistance. For this,a resistance $r_s$ is connected to the galvanometer. Which of the following connections should be employed if the measured current is within $1\%$ of the current without the ammeter in the circuit?

Two galvanometers $A$ and $B$ require currents of $4 \ mA$ and $7 \ mA$,respectively,to produce the same deflection of $20$ divisions. If $S_{A}$ and $S_{B}$ are their sensitivities,respectively,then:

Certain galvanometers have a fixed core made of non-magnetic metallic material. The function of this metallic material is