What is a galvanometer? Give its applications.

$A$ $72 \; \Omega$ galvanometer is shunted by a resistance of $8 \; \Omega$. The percentage of the total current which passes through the galvanometer is $.....$

$A$ galvanometer of resistance $36 \ \Omega$ is converted into an ammeter by using a shunt of $4 \ \Omega$. The fraction $f_0$ of the total current passing through the galvanometer is:

$A$ moving coil galvanometer has $50$ turns and each turn has an area $2 \times 10^{-4} \ m^2$. The magnetic field produced by the magnet inside the galvanometer is $0.02 \ T$. The torsional constant of the suspension wire is $10^{-4} \ N \ m \ rad^{-1}$. When a current flows through the galvanometer,a full-scale deflection occurs if the coil rotates by $0.2 \ rad$. The resistance of the coil of the galvanometer is $50 \ \Omega$. This galvanometer is to be converted into an ammeter capable of measuring current in the range $0-1.0 \ A$. For this purpose,a shunt resistance is to be added in parallel to the galvanometer. The value of this shunt resistance,in ohms,is:

$A$ galvanometer has resistance $G \ \Omega$ and $I_g$ is the current flowing through it which produces full-scale deflection. $S_1$ is the value of the shunt which converts it into an ammeter of range $0$ to $3I$,and $S_2$ is the shunt value which converts it into an ammeter of range $0$ to $4I$. The ratio $S_2:S_1$ is:

Only $4 \%$ of the total current in the circuit passes through a galvanometer. If the resistance of the galvanometer is $G$,then the shunt resistance connected to the galvanometer is: