$A$ galvanometer of resistance $G$ is converted into a voltmeter of range $0-1\, V$ by connecting a resistance $R_{1}$ in series with it. The additional resistance that should be connected in series with $R_{1}$ to increase the range of the voltmeter to $0-2\, V$ will be

$A$ voltmeter of resistance $20000\,\Omega$ reads $5 \text{ V}$. To make it read $20 \text{ V}$,the extra resistance required is

$A$ moving coil galvanometer has $100$ turns and each turn has an area of $2.0 \,cm^2$. The magnetic field produced by the magnet is $0.01 \,T$ and the deflection in the coil is $0.05$ radian when a current of $10 \,mA$ is passed through it. The torsional constant of the suspension wire is $x \times 10^{-5} \,N-m / rad$. The value of $x$ is . . . . . . .

$A$ voltmeter of $250 mV$ range having a resistance of $10 \Omega$ is converted into an ammeter of $250 mA$ range. The value of the necessary shunt is (nearly): (in $\Omega$)

$A$ 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$(s)$.

In the circuit (Figure) the current is to be measured. What is the value of the current if the ammeter shown:
$(a)$ is a galvanometer with a resistance $R_{G}=60.00 \; \Omega$;
$(b)$ is a galvanometer described in $(a)$ but converted to an ammeter by a shunt resistance $r_{s}=0.02 \; \Omega$;
$(c)$ is an ideal ammeter with zero resistance?