Why is parallel arrangement used in domestic wiring?

In a household electric circuit,different appliances are connected in parallel to one another. Give two reasons for this. An electrician puts a fuse of rating $5 \, A$ in that part of a domestic electrical circuit in which an electrical heater of rating $1.5 \, kW, 220 \, V$ is operating. What is likely to happen in this case and why? What change,if any,needs to be made?

What is the $SI$ unit of electric potential?

Give reasons for the following:
$(i)$ Tungsten is used almost exclusively for the filament of electric lamps.
$(ii)$ Why do we use copper and aluminium wires for the transmission of electric current?

$1 \; kWh = \ldots \ldots \; \text{joules}$

Of which physical quantity is the $joule/coulomb$ a unit?