$A$ cell of constant $e.m.f.$ is first connected to a resistance $R_1$ and then connected to a resistance $R_2$. If the power delivered in both cases is the same,then the internal resistance of the cell is:

The actual value of resistance $R$,shown in the figure is $30\,\Omega$. This is measured in an experiment as shown using the standard formula $R_{measured} = \frac{V}{I}$,where $V$ and $I$ are the readings of the voltmeter and ammeter,respectively. If the measured value of $R$ is $5\%$ less than the actual value,then the internal resistance of the voltmeter 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:

As shown in the figure,the voltmeter reads $2\,V$ across the $5\,\Omega$ resistor. The resistance of the voltmeter is $.......\,\Omega$.

In the circuit shown in the figure,the potential difference between points $A$ and $B$ is........

$A$ 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 ............. $\Omega$.