The reading of an ideal voltmeter in the circuit shown is.....$V$.

$A$ $dc$ source of $emf \, E_1 = 100 \, V$ and internal resistance $r = 0.5 \, \Omega$,a storage battery of $emf \, E_2 = 90 \, V$,and an external resistance $R$ are connected as shown in the figure. For what value of $R$ will no current pass through the battery $E_2$ (in $.5$)? ................ $\Omega$

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

For the given circuit,the $emf$ of the cells are $E_1 = 4 \, V$ and $E_2 = 8 \, V$,and their internal resistances are $0.5 \, \Omega$ and $1 \, \Omega$ respectively. Calculate the terminal voltage of each cell.

In the figure shown,the capacity of the capacitor $C$ is $2\,\mu F$. The current in the $2\,\Omega$ resistor is ............... $A$.

The equivalent resistance between $A$ and $B$ is ............ $\Omega$.