N-type Semiconductor Holes – Rankers Physics

P-N Junction Diode and its applications: Practice Problem & Solution

Assertion (A): In a N-type semiconductor, the number of holes get reduced. Reason (R): Rate of recombination of holes would increase due to the increase in the number of electrons  
Both (A) & (R) are true and the (R) is the correct explanation of the (A)
Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(A) is true but (R) is false
Both (A) and (R) are false

Short Solution (Best for NEET):

To solve this problem, we apply the core principles of P-N Junction Diode and its applications. Understanding the underlying formula is key to arriving at the correct answer below:

Assertion (A) is true; in an N-type semiconductor, donor doping increases electron concentration, which, by mass action law (\(np=n_i^2\)), reduces the equilibrium hole concentration. Reason (R) is true; the increased number of electrons in an N-type semiconductor leads to a higher rate of recombination with the minority holes. (R) correctly explains (A) as this increased recombination helps establish and maintain the lower equilibrium hole concentration.

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