Question

For semiconductors, the major factor affecting the value of resistivity when temperature changes is
A. The number of free electrons per unit volume
B. The charge of an electron
C. The mass of an electron
D. Average time between collisions

Answer 1

Hint:Resistivity is a measurement of a material's resistance to electrical conduction at a given size. Although these terms are less often used, resistivity may often be referred to as real electrical resistance or volume resistivity.

Complete answer:
We shall discuss the major factor affecting the value of resistivity when the temperature changes.

A. The quantity of free electrons per unit volume: Temperature increases the number of free electrons per unit length, which more than compensates for any reduction in relaxation time. As a result, the resistivity of semiconductors decreases as the temperature increases.

B. The charge of an electron: the charge of an electron does not affect the value of resistivity when the temperature changes. Hence, this answer is not correct.

C. The mass of an electron: the mass of an electron does not affect the value of resistivity when the temperature changes. Hence, this answer is not correct.

D. The average time between collisions: the average time between collisions does not affect the value of resistivity when the temperature changes. Hence, this answer is not correct.

For semiconductors, the primary factor affecting the value of resistivity when temperature changes is the number of free electrons per unit volume.

Therefore, the correct answer is option A.

Note:A substance with high resistivity has a high resistance to electron flow and can resist it. A substance with a low resistivity has a low resistance, allowing electrons to pass freely through it. Copper and aluminium, for example, have low resistivity. The resistivity of good conductors is lower.