In pure silicon at room temperature, match the event in List-I with i…

The correct answer is Option (1) → (A)-(I), (B)-(II), (C)-(III), (D)-(IV)

(A) A covalent bond breaks — This matches (I). Thermal energy frees one electron from the bond. The vacancy left behind is a hole, so the two appear together.

(B) An electric field is applied — This matches (II). Free electrons give the electron current \(I_e\) and holes give the hole current \(I_h\). The total current is \(I = I_e + I_h\).

(C) An electron from a nearby bond jumps into a vacancy — This matches (III). The vacancy is now at the site the electron came from, so the hole seems to have moved there.

(D) The rate of generation equals the rate of recombination — This matches (IV). Pairs form and disappear at the same rate. This is equilibrium, and the carrier numbers do not change.

NCERT (2026-27):
Intrinsic Semiconductor – “The neighbourhood, from which the free electron (with charge –q) has come out leaves a vacancy with an effective charge (+q). This vacancy with the effective positive electronic charge is called a hole.”

Intrinsic Semiconductor – “… The total current, I is thus the sum of the electron current I_e and the hole current I_h …”

Intrinsic Semiconductor – “An electron from the covalent bond at site 2 may jump to the vacant site 1 (hole). Thus, after such a jump, the hole is at site 2 and the site 1 has now an electron. Therefore, apparently, the hole has moved from site 1 to site 2.”

Intrinsic Semiconductor – “… At equilibrium, the rate of generation is equal to the rate of recombination of charge carriers. …”