$A$ wire of resistance $10\, \Omega$ is bent into a circle. $P$ and $Q$ are two points on the circumference of the circle that divide the circle into a quadrant. When these two points are connected to a battery of $3\, V$ and internal resistance $1\, \Omega$, the currents passing through the two parts of the circle are:

The ends of an element of zinc wire are kept at a small temperature difference $\Delta T$ and a small current $I$ is passed through the wire. Then, the heat developed per unit time

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

$A$ coil takes $15\,min$ to boil a certain amount of water,and another coil takes $20\,min$ for the same process. What is the time taken to boil the same amount of water when both coils are connected in series?

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

The dimension of the quantity $\frac{L}{RCV}$ is