A metal plate of area 1 × 10 - 4   m 2 is illuminated by a radiation of intensity 16   m i l…

A metal plate of area 1×10-4 m2 is illuminated by a radiation of intensity 16 milli Wm2 . The work function of the metal is 5 eV. The energy of the incident photons is 10 eV and only 10% of it produces photo electrons. The number of emitted photo electron  per second and their maximum energy, respectively, will be: 1 eV=1.6×10-19J
  1. 1014 and 10eV
  2. 1012 and 5eV
  3. 1011 and 5eV
  4. 1010 and 5eV

Solution

Einstein's photoelectric equation
Maximum KE=hCλ-ϕ

=10-5

=5 eV

Intensity I=NphCλtANpt=IAhCλ

and number of electrons per second. =Npt×10%

=IAhCλ×110=16×10-3×10-410×1.6×10-19×10

=1011 per sec

Asked in: JEE Main 2019 (10 Jan Shift 2)

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