What are solutions that conduct electricity called?

What is the commercial unit of electrical energy? Represent it in terms of joules.

An electric bulb rated $220 \, V, 60 \, W$ is working at full efficiency. $(i)$ State the resistance of the coil of the bulb. Another identical bulb is connected in series with the first one and the system is connected across the mains as shown below. $(ii)$ State the rate of conversion of energy in each bulb. $(iii)$ Calculate the total power. $(iv)$ What will be the total power if the bulbs are connected in parallel?

An electric iron has a rating of $750\, W; 200\, V$. Calculate:
$(i)$ The current required.
$(ii)$ The resistance of its heating element.
$(iii)$ Energy consumed by the iron in $2$ hours.

Which of the following is true for a parallel combination of two resistors?

If a current of $0.5\;A$ is passed through an electric bulb for $1\;hour$, how much electric charge will pass through the bulb (in $C$)?