Question

Why should we not connect a heater and a bulb in series?

Answer 1

because they need of widely different values to operate properly another major disadvantage of a series circuit is that one component fails the circuit is broken and none of them works

Answer 2

Appliances are preferred to be connected in parallel.

This is because:
* Each appliance can have a separate switch.[ so that both the appliance           doesn't functions at the same time.
* The failure of one appliance doesn't bother the other.[ in series failure of an  appliance disconnects the circuit.


                              Hope it helps.......................