To convert a galvanometer into an ammeter,we connect . . . . . . .

$A$ galvanometer,whose resistance is $50\, \Omega$,has $25$ divisions. When a current of $4 \times 10^{-4}\, A$ passes through it,its needle deflects by one division. To use this galvanometer as a voltmeter of range $2.5\, V$,it should be connected to a resistance of ....... $\Omega$.

$A$ galvanometer has a resistance of $50 \ \Omega$ and it allows a maximum current of $5 \ mA$. It can be converted into a voltmeter to measure up to $100 \ V$ by connecting in series a resistor of resistance: (in $Omega$)

The sensitivity of a galvanometer that measures current is decreased by $\frac{1}{40}$ times by using a shunt resistance of $10 \Omega$. Then,the value of the resistance of the galvanometer is (in $Omega$)

In the moving coil galvanometer,if the number of turns in the coil is doubled,then the current sensitivity . . . . . . and the voltage sensitivity . . . . . . .

If only $\frac{1}{51}$ of the main current is to be passed through a galvanometer,then the shunt required is $R_1$. If only $\frac{1}{11}$ of the main voltage is to be developed across the galvanometer,then the resistance required is $R_2$. Find the ratio $\frac{R_2}{R_1}$.