Question

The electrical resistivity of four materials A ,B, C and D are given as

A=110×10^-8 ohm metre

B=1×10¹⁰ ohm metre

C=10×10^-8 ohm metre

D=2.3×10³ ohm metre

which material is

1) good material

2) resistor

3) insulator

4) semi-conductor

Give reasons for your answer.

Answer 1

C has the lowest resistivity and hence is a good material. A has the next lowest resistivity and hence can be said to be a semi-conductor.
Now a resistor allows electricity to flow through it offering some resistance to the flow whereas an insulator does not allow electricity to flow through it at all and hence we can say that the resistivity of an insulator is very high as compared to that of a resistor. Accordingly we can say that D is a resistor and B is an insulator.

Solution:
1) C
2) D
3) B
4) A