$A$ cell sends a current of $0.9\, A$ through a resistance of $2\, \Omega$ and a current of $0.3\, A$ through a resistance of $7\, \Omega$. The internal resistance of the cell is ............. $\Omega$.

$A$ thermocouple is formed by two metals $X$ and $Y$. Metal $X$ comes earlier than $Y$ in the Seebeck series. If the temperature of the hot junction increases beyond the temperature of inversion,then the direction of the current in the thermocouple will be:

In the circuit shown,wire $1$ is of negligible resistance. Then,

In the given circuit,an ideal voltmeter connected across the $10\,\Omega$ resistance reads $2\,V$. The internal resistance $r$ of each cell is ................... $\Omega$.

For ensuring the dissipation of the same energy in all three resistors $(R_1, R_2, R_3)$ connected as shown in the figure,their values must be related as:

The current flowing in the given circuit is $0.1\,A$. The potential difference between the points $X$ and $Y$ is ................ $V$.