$A$ galvanometer having a resistance of $20\,\Omega$ and $30\,divisions$ on both sides has a figure of merit of $0.005\,A/division$. The resistance that should be connected in series so that it can be used as a voltmeter up to $15\,V$ is ........... $\Omega$.

Explain the solution to the difficulties that arise when using a galvanometer directly as an ammeter.

$A$ galvanometer having a coil of resistance $30 \ \Omega$ needs $20 \ \text{mA}$ of current for full-scale deflection. If a maximum current of $3 \ \text{A}$ is to be measured using this galvanometer,the resistance of the shunt to be added to the galvanometer should be $\frac{30}{X} \ \Omega$,where $X$ is

When a resistance of $200 \Omega$ is connected in series with a galvanometer of resistance $G$,its range is $V$. To triple its range,a resistance of $2000 \Omega$ is connected in series. The value of $G$ is (in $\Omega$)

$A$ multirange voltmeter can be constructed by using a galvanometer circuit as shown in the figure. We want to construct a voltmeter that can measure $2 \ V$,$20 \ V$,and $200 \ V$ using a galvanometer of resistance $10 \ \Omega$ that produces maximum deflection for a current of $1 \ mA$. Find $R_1$,$R_2$,and $R_3$ that have to be used.

$A$ galvanometer of resistance $50 \Omega$ is converted to an ammeter. After shunting,the effective resistance of the ammeter is $2.5 \Omega$. The value of the shunt is