question_answer 4)

In an unbiased p-n junction, holes diffuse from the p-region to w-region because free electrons in the p'region attract them. (b) they move across the junction by the potential difference. (c) hole concentration in p-region is more as compared to n-region. (d) All the above.  

Answer:

(c) hole concentration in p-region is more as compared to p-region because hole diffusion takes place from higher concentration to lower concentration.