Two current elements $P$ and $Q$ have current-voltage characteristics as shown below. Which of the graphs given below best represents the current-voltage characteristics when $P$ and $Q$ are in series?

When a current $I$ is passed through a wire of constant resistance,it produces a potential difference $V$ across its ends. The graph drawn between $\log I$ and $\log V$ will be:

Two cells $A$ and $B$ of emf $2 \text{ V}$ and $1.5 \text{ V}$ respectively, are connected as shown in the figure through an external resistance $10 \text{ } \Omega$. The internal resistance of each cell is $5 \text{ } \Omega$. The potential difference $V_{A}$ and $V_{B}$ across the terminals of the cells $A$ and $B$ respectively are:

Consider the following two statements $A$ and $B$,and identify the correct choice out of the given answers:
$A$. Thermo $e.m.f.$ is minimum at the neutral temperature of a thermocouple.
$B$. When two junctions made of two different metallic wires are maintained at different temperatures,an electric current is generated in the circuit.

$A$ galvanometer $(G)$ of $2 \ \Omega$ resistance is connected in the given circuit. The ratio of charge in $C_1$ $(4 \ \mu F)$ and $C_2$ $(6 \ \mu F)$ is:

When a current is passed through water,acidified with a dilute sulphuric acid,the gases formed at the platinum electrodes are