In the network shown in the figure,the potential difference across the $2R$ resistor is...... (The cell has an $emf$ $E$ and no internal resistance).

The current flowing in a coil of resistance $90 \,\Omega$ is to be reduced by $90\%$. What value of resistance should be connected in parallel with it? ............. $\Omega$

Three identical bulbs are connected as shown in the figure. When switch $S$ is closed,the power consumed in bulb $B$ is $P$. What will be the power consumed by the same bulb when switch $S$ is opened?

Three resistors having resistances $r_{1}, r_{2}$ and $r_{3}$ are connected as shown in the given circuit. The ratio $\frac{i_{3}}{i_{1}}$ of currents in terms of resistances used in the circuit is :

Two resistances $R_1$ and $R_2$ are made of different materials. The temperature coefficient of the material of $R_1$ is $\alpha$ and of the material of $R_2$ is $-\beta$. The resistance of the series combination of $R_1$ and $R_2$ will not change with temperature,if $R_1/R_2$ equals

The figure shows a network of resistors and a battery. If $1\,A$ current flows through the branch $CF$,then find the $emf$ $E$ of the battery. (in $,V$)