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) Resistivity of an alloy is generally higher and it does not oxidize easily. So, 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) In series arrangement, same current will flow through all the appliances which is not required and the equivalent resistance becomes higher, hence the current drawn becomes less.
(iii) They are extremely good conductors having a low value of resistivity.