Two resistors of $200\Omega$ and $400\Omega$ are connected in series with a battery of $100\text{ V}$. $A$ bulb rated at $200\text{ V}, 100\text{ W}$ is connected across the $400\Omega$ resistance. The potential drop across the bulb is . . . . . . $\text{V}$.

The total power dissipated in Watts in the circuit shown here is

$A$ battery with an internal resistance of $4\,\Omega$ is connected to a circuit as shown in the figure. For the circuit to receive maximum power,the value of $R$ should be ..... $\Omega$.

$A$ copper voltameter and a silver voltameter are connected in parallel. When a total charge $q$ flows through the voltameters,an equal mass of metal is deposited in each. If the electrochemical equivalents of copper and silver are $z_1$ and $z_2$ respectively,then the charge flowing through the silver voltameter is:

In the electrical circuit shown in the figure,the current $i$ through the side $AB$ containing the $20 \; \Omega$ resistor is:

The smallest temperature difference that can be measured with a combination of a thermocouple of thermo $e.m.f.$ $30\,\mu V$ per degree and a galvanometer of $50\,\Omega$ resistance,capable of measuring a minimum current of $3 \times 10^{-7} \, A$ is ............... $^\circ C$.