Certain galvanometers have a fixed core made of non-magnetic metallic material. The function of this metallic material is

The current sensitivity of a moving coil galvanometer is increased by $25 \%$. This increase is achieved only by changing the number of turns of the coils and the area of the cross-section of the wire while keeping the resistance of the galvanometer coil constant. The percentage change in the voltage sensitivity will be $...........\%$

Voltmeters $V_1$ and $V_2$ are connected in series across a $D.C.$ line. $V_1$ reads $80 \, V$ and has a resistance per volt of $200 \, \Omega/V$. $V_2$ has a total resistance of $32 \, k\Omega$. The line voltage is ............. (in $V$)

An ideal ammeter and an ideal voltmeter have resistances of . . . . . . $\Omega$ and . . . . . . $\Omega$ respectively.

$A$ galvanometer has a resistance of $25 \, \Omega$ and a maximum of $0.01 \, A$ current can be passed through it. In order to change it into an ammeter of range $10 \, A$, the shunt resistance required is

In an ammeter,$4 \%$ of the main current is passing through the galvanometer. If the shunt resistance is $5 \Omega$,then the resistance of the galvanometer will be: (in $\Omega$)