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JEE Advanced levelOne or more correct optionsDifficulty 3 of 3as054

A metal surface emits photoelectrons under monochromatic light. The incident power is kept constant, but the frequency is raised (still above threshold). Assuming a fixed fraction of absorbed photons ejects electrons, which statements are correct?

  1. AThe number of photons arriving per second decreases
  2. BThe maximum kinetic energy of the electrons increases
  3. CThe stopping potential remains unchanged
  4. DThe saturation photocurrent increases

Answer: A, B

Power = (photons per second) x h nu, so a larger nu at constant power means fewer photons per second and hence a smaller saturation current. Maximum kinetic energy h nu - W and the stopping potential both increase with nu. So the first two statements are correct.
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