The sensitivity of a galvanometer of resistance $406\, \Omega$ is decreased by $30$ times. The shunt used is .................. $\Omega$.

$A$ galvanometer has $30$ divisions and a current sensitivity of $20 \, \mu A$ per division. Its resistance is $25 \, \Omega$. How will you convert this galvanometer into a voltmeter of $1 \, V$ range? (Find the series resistance in $\Omega$)

$A$ certain current passing through a galvanometer produces a deflection of $100$ divisions. When a shunt of $1 \ \Omega$ is connected, the deflection reduces to $1$ division. The galvanometer resistance is: (in $\Omega$)

$A$ voltmeter has a range $0-V$ with a series resistance $R$. With a series resistance $2R$,the range is $0-V'$. The correct relation between $V$ and $V'$ is

$A$ galvanometer of resistance $G$ is shunted by a resistance $S$. To keep the main current in the circuit unchanged,what value of resistance should be connected in series with the galvanometer?

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