Question

The electrical resistivities of four materials P, Q, R and S are given below:

P	`6.84xx10^8`Ωm
Q	`1.70xx10^8`Ωm
R	` 1.0xx10^15`Ωm
s	`11.0xx10^-7`Ωm

Which material will you use for making: (a) heating element of electric iron (b) connecting wires of electric iron (c) covering of connecting wires? Give reason for your choice in each case.

 

Answer 1

Material S will be used for making the heating element of an electric iron as it has a high resistivity .   

 Material Q will be used for making the connecting wires of an electric iron as it has a low resistivity 

 Material R will be used for making the covering of the connecting wires as it has an extremely high resistivity.