To verify Ohm's law,a student is provided with a test resistor $R_T$,a high resistance $R_1$,a small resistance $R_2$,two identical galvanometers $G_1$ and $G_2$,and a variable voltage source $V$. The correct circuit to carry out the experiment is

With a resistance $X$ connected in series with a galvanometer of resistance $100 \Omega$,it acts as a voltmeter of range $0-15 \ V$. To double the range,a resistance of $1500 \Omega$ is to be connected in series with $X$. The value of $X$ in ohm is:

When a resistance of $5\,\Omega$ is shunted with a moving coil galvanometer,it shows a full scale deflection for a current of $250\,mA$. However,when a $1050\,\Omega$ resistance is connected with it in series,it gives full scale deflection for $25\,V$. The resistance of the galvanometer is $......\,\Omega$.

$A$ 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

When a galvanometer is shunted by a resistance $S$, its current capacity increases $n$ times. If the same galvanometer is shunted by another resistance $S'$, its current capacity will increase to $n'$. The value of $n$ in terms of $n'$, $S$, and $S'$ is

The resistance of an ammeter is $13\, \Omega$ and its scale is graduated for a current up to $100\, A$. After an additional shunt has been connected to this ammeter,it becomes possible to measure currents up to $750\, A$ by this meter. The value of the shunt resistance is: