$A$ cell of emf $\varepsilon$ and internal resistance $r$ is connected across a variable load resistance $R$. The graph drawn between its terminal voltage $V$ and resistance $R$ is

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

$A$ copper voltameter is connected in parallel with a heater coil of resistance $0.1\,\Omega$. $A$ current is passed for $20\,\text{minutes}$,resulting in the deposition of $0.99\,\text{g}$ of copper on the cathode. If the electrochemical equivalent of copper is $0.00033\,\text{g/C}$,the heat produced in the coil is ........... $J$.

The resistance of the filament of a lamp increases with the increase in temperature. $A$ lamp rated $100\, W, 220\, V$ is connected across a $220\, V$ power supply. If the voltage drops by $10\%$,then the power of the lamp will be:

Statement $(I)$: The temperature coefficient of resistance for most metals in pure form is positive.
Statement $(II)$: $A$ metal wire $2 \ mm$ in diameter carries a charge of $360 \pi \ C$ in two hours. If the metal contains $5 \times 10^{22}$ free electrons $/ cm^3$, then the drift velocity of the electrons in the wire is $6.25 \times 10^{-6} \ m/s$.
Statement $(III)$: Semiconductors like pure germanium do not obey Ohm's law for all ranges of electric field values. Which of the following is correct?

The potential difference across $8\,\Omega$ resistance is $48\,V$ as shown in the figure. The value of potential difference across $X$ and $Y$ points will be ............. $V$.