$A$ voltmeter having a resistance of $50 \times 10^3 \, \Omega$ is used to measure the voltage in a circuit. To increase the range of measurement $3$ times,the additional series resistance required is:

For a moving coil galvanometer,the deflection in the coil is $0.05\,rad$ when a current of $10\,mA$ is passed through it. If the torsional constant of the suspension wire is $4.0 \times 10^{-5}\,Nm\,rad^{-1}$,the magnetic field is $0.01\,T$,and the number of turns in the coil is $200$,the area of each turn (in $cm^2$) is:

$A$ galvanometer has a resistance of $50 \ \Omega$ and it allows a maximum current of $5 \ mA$. It can be converted into a voltmeter to measure up to $100 \ V$ by connecting in series a resistor of resistance: (in $\Omega$)

The sensitiveness of a moving coil galvanometer can be increased by decreasing:

To reduce the current flowing through a coil of resistance $90\, \Omega$ by $90\%$,a resistor of what value in $\Omega$ must be connected in parallel?

$A$ galvanometer with a resistance of $8 \, \Omega$ is connected to a shunt of $2 \, \Omega$. If the total current is $1 \, A$,how much current in $A$ passes through the shunt?