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(A): When a donor electron is excited to...

(A): When a donor electron is excited to the conduction band no hole is created
(R): Donor energy level does not exist in the valence band.

A

Both 'A' and 'R' are true and 'R' is the correct explanation of 'A'

B

Both 'A' and 'R' are true and 'R' is not the correct explanation of 'A'

C

'A' is true and 'R' is false

D

'A' is false and 'R' is true

Text Solution

AI Generated Solution

The correct Answer is:
To solve the question, we need to analyze both the assertion and the reason provided. ### Step-by-Step Solution: 1. **Understanding the Assertion**: - The assertion states: "When a donor electron is excited to the conduction band, no hole is created." - In semiconductors, donor electrons are those that come from donor atoms (which have extra electrons). When these electrons gain enough energy, they can be excited from the donor energy level to the conduction band. 2. **Analyzing the Assertion**: - When a donor electron moves to the conduction band, it does not leave behind a hole in the valence band. This is because the donor electron is not originally in the valence band; it is in the donor energy level, which is situated just below the conduction band. Therefore, the assertion is true. 3. **Understanding the Reason**: - The reason states: "Donor energy level does not exist in the valence band." - The donor energy level is indeed located just below the conduction band and above the valence band. It does not exist in the valence band itself, which is where the holes are created when electrons are excited from the valence band. 4. **Analyzing the Reason**: - Since the donor energy level is not part of the valence band, the reason is also true. 5. **Conclusion**: - Both the assertion and the reason are true. Furthermore, the reason correctly explains the assertion because the absence of a hole is a direct consequence of the donor energy level's position relative to the conduction and valence bands. ### Final Answer: Both the assertion (A) and the reason (R) are true, and R is the correct explanation of A.
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