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NEET2020PhysicsDual Nature of MatterActual

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?

Options

  1. Afour times
  2. Bone-fourth
  3. Czero
  4. Ddoubled

Correct answer

C. zero

Step-by-step solution

K 1 = 1 . 5   h v 0 − ϕ 0 = 0 . 5   h v 0 K 2 = 1 . 5 h v 0 2 − h v 0 = − 0 . 25   h v 0 ∵ Kinetic energy can never be negative so, no emission and i = 0 OR In second case the incident frequency is halved Incident frequency = 1 . 5 2 v 0 = 0 . 75   v 0 Now the incident frequency is less than threshold frequency, so no emission of electron take place therefore no current. i = 0

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