In an unbiased p-n junction, holes diffuse from the p-region to n-reg…

The correct answer is Option (3) → hole concentration in p-region is more as compared to n-region (due to concentration gradient)

Diffusion is the movement of particles from a region of higher concentration to a region of lower concentration; it needs no force, only a concentration gradient. Holes are the majority carriers in the p-region and very few in the n-region, so they diffuse from p to n.

Option (1) free electrons in the n-region attract them — Incorrect. That would be a drift under an electric field, not diffusion.

Option (2) they move across the junction due to the potential difference — Incorrect. The barrier potential is set up by the diffusion itself and opposes further diffusion.

Option (4) hole concentration in n-region is more as compared to p-region — Incorrect. Holes are minority carriers in the n-region; this reverses the gradient.

Note: A similar question was also asked in CUET (UG) 2026 on 06-06-2026 (Slot 1).

NCERT (2026-27):
p-n Junction Formation – “… During the formation of p-n junction, and due to the concentration gradient across p-, and n- sides, holes diffuse from p-side to n-side (p → n) and electrons diffuse from n-side to p-side (n → p). This motion of charge carries gives rise to diffusion current across the junction.”