Two galvanometers $A$ and $B$ require currents of $4 \ mA$ and $7 \ mA$,respectively,to produce the same deflection of $20$ divisions. If $S_{A}$ and $S_{B}$ are their sensitivities,respectively,then:

$A$ moving coil galvanometer is converted into an ammeter, reading up to $0.04 \,A$ by connecting a shunt of resistance '$3r$' across it and then into an ammeter reading up to $0.8 \,A$, when a shunt of resistance '$r$' is connected across it. What is the maximum current which can be sent through this galvanometer if no shunt is used (in $\,A$)?

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?

$A$ galvanometer $G$ deflects full scale when a potential difference of $0.50 \ V$ is applied. The internal resistance of the galvanometer $r_g$ is $25 \ \Omega$. An ammeter is constructed by incorporating the galvanometer and an additional shunt resistance $R_S$. The ammeter deflects full scale when a measurement of $2.0 \ A$ is made. The resistance $R_S$ is closest to : ................. $\Omega$

$A$ galvanometer coil has a resistance of $12\,\Omega$ and the meter shows full-scale deflection for a current of $3\,mA$. To convert it into a voltmeter of range $0-18\,V$,what resistance should be added and how?

If a galvanometer is shunted by $(\frac{1}{n-1})^{th}$ of the value of its resistance, then the fraction of the total current passing through the galvanometer is