Concept:In an intrinsic semiconductor, free electrons and holes are always created in equal numbers.
Explanation:An intrinsic semiconductor is a pure semiconductor without any impurity atoms.
Thermal energy excites an electron from the valence band to the conduction band.
Every time one free electron is created, one hole is left behind in the valence band.
Therefore, the two are produced together as electron-hole pairs.
No process in an intrinsic semiconductor creates one without the other at thermal equilibrium.
So the number of holes equals the number of free electrons.
This can be written as
np=ne.
Answer:The number of holes in an intrinsic semiconductor is equal to the number of free electrons.
Correct option: C.