$A$ galvanometer has a resistance of $100 \, \Omega$ and a full-scale range of $50 \, \mu A$. It can be used as a voltmeter or as a high-range ammeter provided a resistance is added to it. Pick the correct range and resistance combination.

The sensitivity of a galvanometer that measures current is decreased by $\frac{1}{40}$ times by using a shunt resistance of $10 \Omega$. Then,the value of the resistance of the galvanometer is (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:

For designing a voltmeter of range $50\,V$ and an ammeter of range $10\,mA$ using a galvanometer which has a coil of resistance $54\,\Omega$ showing a full scale deflection for $1\,mA$ as in figure.
$(A)$ for voltmeter $R \approx 50\,k\Omega$
$(B)$ for ammeter $r \approx 0.2\,\Omega$
$(C)$ for ammeter $r \approx 6\,\Omega$
$(D)$ for voltmeter $R \approx 5\,k \Omega$
$(E)$ for voltmeter $R \approx 500 \Omega$
Choose the correct answer from the options given below

Consider a moving coil galvanometer $(MCG)$ :
$A :$ The torsional constant in a moving coil galvanometer has dimensions $[ML^2 T^{-2}]$.
$B :$ Increasing the current sensitivity may not necessarily increase the voltage sensitivity.
$C :$ If we increase the number of turns $(N)$ to its double $(2N)$,then the voltage sensitivity doubles.
$D :$ $MCG$ can be converted into an ammeter by introducing a shunt resistance of a large value in parallel with the galvanometer.
$E :$ Current sensitivity of $MCG$ depends inversely on the number of turns of the coil.
Choose the correct answer from the options given below:

$A$ galvanometer coil has a resistance of $12\; \Omega$ and the meter shows full-scale deflection for a current of $3\; mA$. How will you convert the meter into a voltmeter of range $0$ to $18\; V$?