Question

The expelled excited electron from chlorophyll-a after photo excitation comes back to ground state in ___________.

• A. $10^{-9}$ minutes
• B. $10^{-8}$ minutes
• C. $10^{-8}$ hours
• D. $10^{-9}$ seconds

Hint:

Excited chlorophyll electron returns to ground state in {one nanosecond ($10^{-9}$ s)}.

Answer 1

The Correct Option is D

Step 1: Photoexcitation of chlorophyll.
When chlorophyll-a absorbs light energy, its electrons get excited to a higher energy level.
Step 2: Return to ground state.
If the excited electron does not participate in photochemical reactions, it quickly returns to the ground state.
Step 3: Time duration.
The excited electron returns to the ground state within $10^{-9$ seconds}, releasing excess energy as heat or fluorescence.