$A$ galvanometer of resistance $100 \Omega$ gives full scale deflection for a current of $1 \text{ mA}$. It is converted into an ammeter of range $0 - 10 \text{ A}$. The shunt required is: (in $\text{ }\Omega$)

The pole pieces of the magnet used in a pivoted coil galvanometer are

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

Derive the expression for the shunt resistance required to increase the current-measuring capacity of a galvanometer by a factor of $n$.

The galvanometer has a resistance of $1.8 \Omega$. Calculate the value of shunt to increase the range of galvanometer by $10$ times. (in $\Omega$)

Given below are two statements: One is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A:$ For measuring the potential difference across a resistance of $600\,\Omega$,the voltmeter with resistance $1000\,\Omega$ will be preferred over a voltmeter with resistance $4000\,\Omega$.
Reason $R:$ $A$ voltmeter with higher resistance will draw smaller current than a voltmeter with lower resistance.
In the light of the above statements,choose the most appropriate answer from the options given below.