The current sensitivity of a moving coil galvanometer increases by $20 \%$ when its resistance is doubled. Calculate,by what factor does the voltage sensitivity change?

$A$ galvanometer is used in a laboratory for detecting the null point in electrical experiments. If, on passing a current of $6 \ mA$, it produces a deflection of $2^{\circ}$, its figure of merit is close to (each division is $1^{\circ}$):

The number of turns in a coil of a galvanometer is tripled. Then:

Two identical galvanometers are converted into an ammeter and a milliammeter. For the same current,the value of the shunt of the ammeter as compared to that of the milliammeter is

$A$ millivoltmeter of $25 \, mV$ range is to be converted into an ammeter of $25 \, A$ range. The value (in $\Omega$) of the necessary shunt will be:

$A$ multirange voltmeter can be constructed by using a galvanometer circuit as shown in the figure. We want to construct a voltmeter that can measure $2 \ V$,$20 \ V$,and $200 \ V$ using a galvanometer of resistance $10 \ \Omega$ that produces maximum deflection for a current of $1 \ mA$. Find $R_1$,$R_2$,and $R_3$ that have to be used.