$A$ galvanometer of resistance $G$ can be converted into a voltmeter of range $V$ by connecting a resistance $R$ in series with it. The series resistance required to change its range to $\frac{V}{3}$ is

$A$ galvanometer has a coil of resistance $200 \Omega$ with a full scale deflection at $20 \mu A$. The value of resistance to be added to use it as an ammeter of range $(0-20) mA$ is: (in $Omega$)

$A$ galvanometer having a coil resistance $100 \; \Omega$ gives a full-scale deflection when a current of $1 \; mA$ is passed through it. What is the value of the resistance in $k\Omega$ which can convert this galvanometer into a voltmeter giving full-scale deflection for a potential difference of $10 \; V$?

Current sensitivities of two galvanometers $G_1$ and $G_2$ of resistances $100 \ \Omega$ and $50 \ \Omega$ are $10^8 \ \text{div/A}$ and $0.5 \times 10^5 \ \text{div/A}$ respectively. The galvanometer in which the voltage sensitivity is more is

What is a galvanometer? Give its applications.

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 $M_{1}$.