The value of the shunt resistance that allows $10 \%$ of the main current through the galvanometer of $99 \Omega$ is (in $Omega$)

Consider the following two statements $A$ and $B$ and identify the correct choice given in the answers.
$A$. Duddell's thermo-galvanometer is suitable to measure direct current only.
$B$. Thermopile can measure temperature differences of the order of $10^{-3} \, ^\circ C$.

Why is the total resistance of a voltmeter kept very high?

The sensitivity of a galvanometer is $60 \text{ division/A}$. When a shunt is used,its sensitivity becomes $10 \text{ division/A}$. If the galvanometer is of resistance $20 \ \Omega$,the value of shunt used is (in $Omega$)

The scale of a galvanometer is divided into $160$ equal divisions. The galvanometer shows full scale deflection of $16$ mA and maximum voltage is $80$ mV. Now the range is changed so that the galvanometer reads $160$ $V$. The required resistance to be connected 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: