In the circuit diagrams ($A, B, C$ and $D$) shown below,$R$ is a high resistance and $S$ is a resistance of the order of galvanometer resistance $G$. The correct circuit,corresponding to the half deflection method for finding the resistance and figure of merit of the galvanometer,is the circuit labelled as

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?

For designing a voltmeter of range $50\,V$ and an ammeter of range $10\,mA$ using a galvanometer which has a coil of resistance $54\,\Omega$ showing a full scale deflection for $1\,mA$ as in figure.
$(A)$ for voltmeter $R \approx 50\,k\Omega$
$(B)$ for ammeter $r \approx 0.2\,\Omega$
$(C)$ for ammeter $r \approx 6\,\Omega$
$(D)$ for voltmeter $R \approx 5\,k \Omega$
$(E)$ for voltmeter $R \approx 500 \Omega$
Choose the correct answer from the options given below

Two similar galvanometers are converted into an ammeter and a milliammeter. The shunt resistance of the ammeter as compared to the shunt resistance of the milliammeter will be

State the principle of a moving coil galvanometer.

In an experiment to determine the figure of merit of a galvanometer by the half-deflection method,a student constructed the following circuit. He unplugged a resistance of $5200 \ \Omega$ in $R$. When $K_1$ is closed and $K_2$ is open,the deflection observed in the galvanometer is $26 \ \text{div}$. When $K_2$ is also closed and a resistance of $90 \ \Omega$ is removed in $S$,the deflection becomes $13 \ \text{div}$. The resistance of the galvanometer is nearly: (in $\Omega$)