Identify the correct statement(s) among the following.(A) Electrical…

The correct answer is Option (2) → (B) and (C) only

In a pure semiconductor, heat excites some electrons from the valence band to the conduction band, leaving holes behind; these electrons and holes are the intrinsic charge carriers. Doping adds extra carriers.

(A) Electrical conductivity in an intrinsic semiconductor is due to electrons excited from the conduction band to valence band. — Incorrect. The direction is reversed: electrons are excited from the valence band (lower) to the conduction band (higher).

(B) In germanium atom electrical conductivity is due to intrinsic charge carriers. — Correct. Pure germanium is an intrinsic semiconductor; it conducts through the thermally produced electrons and holes.

(C) In doped atoms, the size of the dopant atom should be almost the same as that of the intrinsic crystal. — Correct. A dopant of about the same size takes the place of a host atom without distorting the crystal lattice.

(D) In n-type semiconductor, the donor atom becomes negatively charged. — Incorrect. A pentavalent donor gives its fifth electron to the conduction band and becomes a positive ion, fixed in the lattice.

NCERT (2026-27):
Intrinsic Semiconductor – “… It is the thermal energy at higher temperatures (T > 0K), which excites some electrons from the valence band to the conduction band.”

Extrinsic Semiconductor – “… The dopant has to be such that it does not distort the original pure semiconductor lattice. … A necessary condition to attain this is that the sizes of the dopant and the semiconductor atoms should be nearly the same.”

p-n Junction Formation – “… When an electron diffuses from n → p, it leaves behind an ionised donor on n-side. This ionised donor (positive charge) is immobile as it is bonded to the surrounding atoms.”