In the following circuit, the magnitude of current $I_1$ is $............A$.

To measure the temperature coefficient of resistivity $\alpha$ of a semiconductor,an electrical arrangement shown in the figure is prepared. The arm $BC$ is made up of the semiconductor. The experiment is being conducted at $25^{\circ} C$ and the resistance of the semiconductor arm $BC$ is $3 \ m\Omega$. Arm $BC$ is cooled at a constant rate of $2^{\circ} C / s$. If the galvanometer $G$ shows no deflection after $10 \ s$,then $\alpha$ is:

$A$ Wheatstone bridge is used to determine the value of an unknown resistance $X$ by adjusting the variable resistance $Y$ as shown in the figure. For the most precise measurement of $X$,the resistances $P$ and $Q$:

The figure shows a network of five resistances and two batteries. The current through the $30\,V$ battery is ............... $A$.

In the circuit shown in the given figure,the resistances $R_1$ and $R_2$ are respectively:

Find the current through the branch $ad$ of the circuit shown in the figure. (in $, A$)