In the circuit shown in the figure. $\left(\mathrm{A}\right)$, $R_3$ is a variable resistance



As the value $R_3$ is changed, current $I$ though the cell varies as shown. Obviously, the variation is asymptotic, i.e. $I\mathrm{ }\to \mathrm{ }6 \mathrm{A}$ as $R_3\to \mathrm{\infty }$ . Ratio of resistances $R_1 \text{and} R_2$ will be: 

In the circuit, wire $1$ is of negligible resistance. Then

A current of $0.1 \mathrm{A}$ flows through a $25 \mathrm{\Omega }$ resistor represented by the circuit diagram. The current in the $80 \mathrm{\Omega }$ resistor is:

The potential difference $\left(V_{\mathrm{A}}-V_{\mathrm{B}}\right)$ between the points $A$ and $B$ in the given figure is

For a diode connected in parallel with a resistor, which is the most likely current $\left(I\right)$-voltage $\left(V\right)$ characteristic graph?

The figure below shows a circuit and its input voltage $V_i$ as a function of time $t$.

Assuming the diodes to be ideal, which of the following graphs depicts the output voltage $V_o$ as function of time $t ?$

Two batteries of emfs $\mathrm{4\; V}$ and $\mathrm{8\; V}$ with internal resistances $\mathrm{1 }\mathrm{\Omega }$ and $\mathrm{2 }\mathrm{\Omega }$ are connected in a circuit with a resistance of $\mathrm{9 }\mathrm{\Omega }$ as shown in figure. The current and potential difference between the points $\mathit{P}$ and $\mathit{Q}$ are,