Question

explain the following :

(i) the elements of electric heating devices such as bread-toasters and electric iron are made of an alloy rather than of a pure metal.

(ii) series arrangement is not used for domestic circuits.

(iii) copper and aluminium wires are usually employed for electricity transmission.

Answer 1

(i)

Alloys are used in electrical heating devices because of two reasons:

• They have higher resistivity, than constituent metals.
• They do not oxidize easily at high temperatures.

(ii)In the series arrangement, due to non uniform voltage if one appliance is affected (or fused) then all other appliance will stop working. Hence series arrangement is not used for domestic circuit.

(iii) Copper and aluminum have less resistance and are good conductors of electricity. Hence copper and aluminum wires are usually employed for electricity transmission.