In a galvanometer,the deflection becomes one half when the galvanometer is shunted by a $20\,\Omega$ resistor. The galvanometer resistance is ............... $\Omega$.

Two identical moving coil galvanometers have $10 \Omega$ resistance and full scale deflection at $2 \mu A$ current. One of them is converted into a voltmeter of $100 \text{ mV}$ full scale reading and the other into an ammeter of $1 \text{ mA}$ full scale current using appropriate resistors. These are then used to measure the voltage and current in the Ohm's law experiment with $R = 1000 \Omega$ resistor by using an ideal cell. Which of the following statement$(s)$ is/are correct?
$(1)$ The measured value of $R$ will be $980.2 \Omega$.
$(2)$ The resistance of the voltmeter will be $50 \text{ k} \Omega$.
$(3)$ The resistance of the ammeter will be $0.02 \Omega$ (rounded off to the $2^{\text{nd}}$ decimal place).
$(4)$ If the ideal cell is replaced by a cell having internal resistance of $5 \Omega$,then the measured value of $R$ will be more than $1000 \Omega$.

Two moving coil meters,$M_{1}$ and $M_{2}$ have the following particulars:
$R_{1}=10 \,\Omega, \quad N_{1}=30$
$A_{1}=3.6 \times 10^{-3} \,m^{2}, \quad B_{1}=0.25 \,T$
$R_{2}=14 \,\Omega, \quad N_{2}=42$
$A_{2}=1.8 \times 10^{-3} \,m^{2}, \quad B_{2}=0.50 \,T$
(The spring constants are identical for the two meters). Determine the ratio of
$(a)$ current sensitivity and
$(b)$ voltage sensitivity of $M_{2}$ and $M_{1}$.

$A$ galvanometer has a resistance of $100 \, \Omega$ and a full-scale range of $50 \, \mu A$. It can be used as a voltmeter or as a high-range ammeter provided a resistance is added to it. Pick the correct range and resistance combination.

The sensitivity of a moving coil galvanometer is $s$. If a shunt of $\frac{1}{8}$ of the resistance of the galvanometer is connected to the moving coil galvanometer,what will its new sensitivity be?

In the circuit shown below,the ammeter and the voltmeter readings are $3 \text{ A}$ and $6 \text{ V}$ respectively. Then the value of the resistance $R$ is