Exam-style question
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What effect does increasing the wavelength of incident light have on the photocurrent of a photodiode?.
- A.The photocurrent increases.
- B.The photocurrent decreases.
- C.The photocurrent remains the same.
- D.The photocurrent becomes negative.
Model answer
What a good answer should say
- The photocurrent decreases.
Explanation
Why this works
The evidence shows that as the wavelength of incident light increases, the energy of the photons decreases, which may not be sufficient to generate electron-hole pairs in the photodiode. This implies that there is a threshold wavelength below which the photodiode operates effectively.
Thus, we conclude that longer wavelengths result in a decrease in photocurrent, limiting the photodiode's effectiveness in certain light conditions.
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