The diagrams show four different ways in which current $I_1,I_2,I_3$, can combine at a junction. For which of these junctions, is the following equation correct?

$I_1+I_2=I_3+I_4$

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 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 with e.m.f. $12 \mathrm{V}$ and $13 \mathrm{V}$ are connected in parallel across a load resistor of $10 \mathrm{\Omega }$. The internal resistance of the two batteries are $1 \mathrm{\Omega }$ and $2 \mathrm{\Omega }$ respectively. The voltage across the load lies between, 

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?

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