NEET 2020 · PhysicsPhotocurrentPrevious Year Question
Light of frequency 1.5 times the threshold frequency is incident on a photosensitive material. What will be the photoelectric current if the frequency is halved and intensity is doubled?
Answer: (B) zero. Answer: (b) zero Solution: New frequency = (1.5ν₀)/2 = 0.75ν₀, which is below the threshold frequency ν₀.
- A.one-fourth
- B.zero✓
- C.doubled
- D.four times
Correct Answer
(B) zero
Solution & Explanation
Answer: (b) zero Solution: New frequency = (1.5ν₀)/2 = 0.75ν₀, which is below the threshold frequency ν₀. No matter how intense, no photoelectrons are emitted below threshold ⇒ photoelectric current is zero.
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