If the internal resistance of a cell is proportional to the current drawn from the cell,then the best representation of the terminal potential difference of the cell with respect to the current drawn from the cell will be:

The heater of an electric kettle is made of a wire of length $L$ and diameter $d$. It takes $4$ minutes to raise the temperature of $0.5 \ kg$ of water by $40 \ K$. This heater is replaced by a new heater having two wires of the same material,each of length $L$ and diameter $2d$. The way these wires are connected is given in the options. How much time in minutes will it take to raise the temperature of the same amount of water by $40 \ K$?
$(A)$ $4$ if wires are in parallel
$(B)$ $2$ if wires are in series
$(C)$ $1$ if wires are in series
$(D)$ $0.5$ if wires are in parallel

Consider the circuit given here. The potential difference $V_{BC}$ between the points $B$ and $C$ is (in $V$)

Four equal resistances dissipate $5 \, W$ of power together when connected in series to a battery of negligible internal resistance. The total power dissipated in these resistances when connected in parallel across the same battery would be ........... $W$.

$A$ $25\, W$, $220\, V$ bulb and a $100\, W$, $220\, V$ bulb are connected in parallel across a $440\, V$ line. Which of the following will happen?

For a given thermocouple,the thermo $e.m.f.$ can be