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 . . . . . . $\text{V}$.

$A$ $100 \ V$ voltmeter having a resistance of $20 \ k\Omega$ is connected in series with a very high resistance $R$. When it is connected to a $110 \ V$ line,it reads $5 \ V$. What is the value of $R$?

$A$ heater is rated $100\ W, 200\ V$. It is cut into two equal parts. Both parts are connected in parallel to the same $200\ V$ source. The energy released per second in this new combination is ............. $W$.

Two voltameters,one of copper and another of silver,are joined in parallel. When a total charge $q$ flows through the voltameters,equal amounts of metals are deposited. If the electrochemical equivalents of copper and silver are $z_1$ and $z_2$ respectively,the charge which flows through the silver voltameter is

$A$ current of $1.5\, A$ flows through a copper voltameter. The thickness of copper deposited on the electrode surface of area $50\, cm^2$ in $20\, min$ will be (Density of copper $= 9000\, kg/m^3$ and $E.C.E.$ of copper $= 0.00033\, g/C$).

In the figure,the current through the $3\,\Omega$ resistor is $0.8\,A$. Then,the potential drop across the $4\,\Omega$ resistor is ........... $V$.