The scale of a galvanometer is divided into $100$ equal divisions. It has a current sensitivity of $10 \text{ div./mA}$ and a voltage sensitivity of $4 \text{ div./mV}$. The resistance of the galvanometer is: (in $\Omega$)

Why should the resistance of an ammeter be as low as possible?

Which one of the following modifications may increase the sensitivity of a moving coil galvanometer?
$1^{st}$ Way: By using a spring of smaller torsion constant.
$2^{nd}$ Way: By using a smaller coil.
$3^{rd}$ Way: By using a stronger magnet.
$4^{th}$ Way: By using a coil having fewer number of turns.

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 $10^{-3} \, ^\circ C$.

For full scale deflection of total $50$ divisions, $50 \, mV$ voltage is required in a galvanometer. The resistance of the galvanometer, if its current sensitivity is $2 \, div/mA$, will be $..... \Omega$.

$A$ voltmeter of $250 mV$ range having a resistance of $10 \Omega$ is converted into an ammeter of $250 mA$ range. The value of the necessary shunt is (nearly): (in $\Omega$)