Question

The heating element in an electric iron is made up of:
A. Nichrome.
B. Iron.
C. Constantan
D. Tungsten.

Answer 1

Hint: The material which can sustain heat at high temperature is suitable for electric iron’s heating element as that part will have to be hot for some time in order to provide heat. The element which should be used as the heating material should not break due to regular temperature variation and should not react with the atmospheric gases at the excited state because that will affect the life of the material and the appliance as well.

Complete step by step solution:
Nichrome is an alloy of nickel and chromium; it is mainly used as heating of elements in various appliances. When the nichrome is heated to red hot temperature then the outer layer develops a chromium oxide layer which acts as a protective layer to the main heating element and also stops further oxidation process which can help in increasing the life of the material.
Some of the properties which make nichrome suitable for heating element for electric iron are:-
(i) It makes an oxide layer on the first time it is heated.
(ii) The oxide formed is stable at high temperatures.
(iii) The oxide formed protects the inner material from getting oxide.
These properties make nichrome a suitable alloy that can be used for the electric iron heating element.

Additional information:
The nichrome is a material made of $80\mathrm{\%}$ nickel and $20\mathrm{\%}$. Nichrome is a material that provides high mechanical strength and also it provides high creep strength.

Note:
Nichrome is an ideal material for heating elements for an electric iron also because the oxide layer formed helps to protect the inner material from oxidizing which doesn’t let internal wires burn.