The value of current through the $20\,\Omega$ resistor is ............ $A$.

In the following network,the current flowing through the $15\Omega$ resistance is: (in $A$)

The heat generated in $1 \text{ minute}$ between points $A$ and $B$ in the given circuit, when a battery of $9 \text{ V}$ with internal resistance of $1 \ \Omega$ is connected across these points, is . . . . . . $J$.

The total length of the potentiometer wire $AB$ is $50 \text{ cm}$ in the arrangement as shown in the figure. If $P$ is the point where the galvanometer shows zero reading, then the length $AP$ is . . . . . . $\text{ cm}$.

In the given circuit,the galvanometer reading is zero. If the internal resistance of the cells is negligible,then the value of $x$ is ............. $\Omega$.

The Wheatstone bridge principle is used to measure the specific resistance $(S_1)$ of a given wire,having length $L$ and radius $r$. If $X$ is the resistance of the wire,then the specific resistance is: $S_1 = X \left( \frac{\pi r^2}{L} \right)$. If the length of the wire is doubled,then the value of the specific resistance will be: