When a galvanometer is shunted by a resistance $S$,its current capacity increases $n$ times. If the same galvanometer is shunted by another resistance $S^{\prime}$,its current capacity increases to $n^{\prime}$. The value of $n^{\prime}$ in terms of $n, S$ and $S^{\prime}$ is

The magnets of two suspended coil galvanometers are of the same strength so that they produce identical uniform magnetic fields in the region of the coils. The coil of the first one is in the shape of a square of side $a$ and that of the second one is circular of radius $\frac{a}{\sqrt{\pi}}.$ When the same current is passed through the coils, the ratio of the torque experienced by the first coil to that experienced by the second one is

$A$ 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 $1^{\circ}$):

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

The value of the shunt resistance that allows $10 \%$ of the main current through the galvanometer of $99 \Omega$ is (in $\Omega$)

$A$ milliammeter of range $10 \, mA$ has a coil of resistance $1 \, \Omega$. To use it as a voltmeter of range $10 \, V$,the resistance that must be connected in series with it will be ............. $\Omega$.