Question

The heater element in an electric iron is made of
A. Copper
B. Tungsten
C. Nichrome
D. Iron
E. Platinum

Answer 1

Hint: In this question remember that for an electric iron heater element should have higher resistance, high melting point and high specific heat, using this information find the element mentioned in the option which will be suitable for electric iron.

Complete answer:
In the given information the mentioned elements are; copper, tungsten, nichrome, iron, platinum
We know that the function of electric iron is to remove wrinkles using pressure and heat.
Since, for using this machine for long term a heating element should not be melted.
We know that there are two conditions under which an element gets melted.

An element should have high resistance so that it can hold its configuration in high voltage current.
It should have a high melting point such that it can sustain high temperature.

So, from all the given Nichrome is used as a heating element in electric iron which is an alloy consisting 80% of Nickel and 20% of Chromium melting point of this element is 1400 degree Celsius with high resistance which makes this element best for using as a heating element.

The reason which makes the Nichrome best for heating elements is when it is heated in the air it develops an outer layer of chromium oxide which makes it stable in air and this chromium layer helps the element from oxidizing further during heating.

So, the correct answer is “Option C”.

Note:
Among all the mentioned elements in the option each element can be used for heating purposes but in order to use as a heating element are formed into thin wire such that it has enough resistance to create required heat. So, as soon the wire gets heated mostly elements oxidize fluently due to which they become brittle and eventually break when heated in air.