Question

Define resistivity of material. State its S. I units and discuss its variation with temperature in case of (i) metals (ii) semiconductors and (iii) insulators.

Answer 1

Resistivity if a material can be defined as the amount of resistance provided by a conductor of 1m length and cross sectional area 1m2.

The SI unit of resistivity is ohm metre

(i) metals have a low resistance, so the resistivity will also be low

(ii) semi-conductors have more resistance than conductors, and hence resistivity will also be more

(iii) insulators have very high resistance, and so the resistivity will also be very high

Answer 2

Answer:

The resistivity of a substance is the resistance of a wire of that substance of unit length and unit area of cross-section. Its S. I. unit is ohm × m.