Why does a galvanometer not show full-scale deflection after connecting it in a circuit?

In a galvanometer,$5 \%$ of the total current in the circuit passes through it. If the resistance of the galvanometer is $G$,the shunt resistance $S$ connected to the galvanometer is

What is a shunt? Explain its function in a circuit,obtain the formula for the shunt,and explain its uses.

$A$ galvanometer of resistance $50 \Omega$ is connected to a battery of $3 \text{ V}$ along with a resistance of $2950 \Omega$ in series. $A$ full-scale deflection of $30$ divisions is obtained in the galvanometer. In order to reduce this deflection to $20$ divisions,the resistance in series should be: (in $Omega$)

With a resistance $X$ connected in series with a galvanometer of resistance $100 \Omega$,it acts as a voltmeter of range $0-15 \ V$. To double the range,a resistance of $1500 \Omega$ is to be connected in series with $X$. The value of $X$ in ohm is:

$A$ galvanometer has a coil of resistance $100 \, \Omega$ and gives a full-scale deflection for $30 \, mA$ current. If it is to work as a voltmeter of $30 \, V$ range,the resistance required to be added will be..... $\Omega$