By connecting a resistance of $980 \Omega$ in series with a galvanometer, it is converted into a voltmeter of a certain range. When the resistance of $470 \Omega$ is connected in series, the range is halved. The resistance of the galvanometer is (in $\Omega$)

What is the resistance of an ideal ammeter?

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:

In a moving coil galvanometer,a strong horse-shoe magnet with concave-shaped pole pieces is used to:

An ammeter of $100 \, \Omega$ resistance gives full-scale deflection for a current of $10^{-5} \, A$. The shunt resistance required to convert it into an ammeter of $1 \, A$ range will be:

$A$ galvanometer has a deflection of $25$ divisions for a current of $0.1 \ A$ flowing through it. Then the current sensitivity of the galvanometer is (in $div/A$)