Question

A person buys two electrical devices P and Q for lighting purposes in his house. The device P consumes only 5 units of electricity in a month but device Q consumes 15 units of electricity in a month when used for the same number of hours daily. The device Q wastes a lot of electricity by radiating energy C but P does not do so.
(a) What type of device is (i) P, and (ii) Q?
(b) Name one component which is present in Q but not in P.
(c) Name the energy C.
(d) Which device is more energy efficient : P or Q?
(e) Which fossil fuel is most likely to be conserved if all of us switch over to devices like P?

Answer 1

(a) (i) P is a CFL (Compact Fluorescent Lamp), and (ii) Q is a filament type bulb.

(b) Filament is present in a bulb, not in CFL.

(c) Energy C is heat energy.

(d) P is more energy efficient.

(e) Coal will be conserved if all of us switch over to devices like P (CFL). This is because it is used in generating electricity.