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 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 atmospheric gases at the excited state.

Complete step by step answer
Nichrome is an alloy of nickel and chromium; it is mostly used as heating of elements in various applications. As soon as the nichrome is heated to red hot temperature then the outer layer forms 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 appropriate for heating element for electric iron are:-
-It creates an oxide layer for the first time it is heated.
-The oxide made is stable at high temperatures.
-The oxide made defends the inner material from getting oxide.
-These properties make nichrome an appropriate alloy that can be used for the electric iron heating element.
Hence, the correct option is (A) Nichrome.

Additional Information
The nichrome is a material made of $80\mathrm{\%}$ nickel and $20\mathrm{\%}$ . Nichrome is a material that delivers high mechanical strength and also it offers high creep strength. It has a high melting point such that it can sustain high temperatures.

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. The alloys offer high strength, excellent fabricability, and outstanding corrosion resistance. These desirable properties are due to the combination of elements that make up this alloy as a heating device.