The deflection in a moving coil galvanometer falls from $50$ divisions to $10$ divisions,when a shunt of $12 \Omega$ is connected with it. The resistance of the galvanometer coil is . . . . . . . (in $\Omega$)

$A$ galvanometer coil of resistance $50 \,\Omega$ shows full-scale deflection for a current of $100 \,\mu A$. The shunt resistance to be added to the galvanometer to convert it into an ammeter of range $10 \, mA$ is:

$STATEMENT-1$: The sensitivity of a moving coil galvanometer is increased by placing a suitable magnetic material as a core inside the coil.
$STATEMENT-2$: Soft iron has a high magnetic permeability and cannot be easily magnetized or demagnetized.

In the circuit (Figure) the current is to be measured. What is the value of the current if the ammeter shown:
$(a)$ is a galvanometer with a resistance $R_{G}=60.00 \; \Omega$;
$(b)$ is a galvanometer described in $(a)$ but converted to an ammeter by a shunt resistance $r_{s}=0.02 \; \Omega$;
$(c)$ is an ideal ammeter with zero resistance?

The deflection in a moving coil galvanometer of resistance $45 \Omega$ falls from $30$ divisions to $3$ divisions. The length of the shunt wire required to convert the galvanometer into an ammeter is [specific resistance of the material of the shunt wire $= 5 \times 10^{-7} \Omega m$ and area of cross-section of the wire $= 4 \times 10^{-7} m^2$]. (in $m$)

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: