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JEE Main 2023 (1 Feb, Shift 2) · Photoelectric Effect: Einstein's Equation

Photoelectric Effect: Einstein's Equation question from JEE Main 2023 (1 Feb, Shift 2)

Q84JEE Main 2023 · 1 FEB · SHIFT 2Medium

Photoelectric Effect: Einstein's Equation

The threshold frequency of a metal is f0f_0. When the light of frequency 2f02f_0 is incident on the metal plate, the maximum velocity of photoelectrons is v1v_1. When the frequency of incident radiation is increased to 5f05f_0, the maximum velocity of photoelectrons emitted is v2v_2. The ratio of v1v_1 to v2v_2 is:

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Answer: (a)

  1. 12mv2=hν−hν0\frac{1}{2}mv^2 = h\nu - h\nu_0
  2. At 2ν02\nu_0: K1=hν0K_1 = h\nu_0; at 5ν05\nu_0: K2=4hν0K_2 = 4h\nu_0
  3. v1v2=14=12\frac{v_1}{v_2} = \sqrt{\frac{1}{4}} = \frac{1}{2}
  4. So the answer is (a) v1v2=12\frac{v_1}{v_2} = \frac{1}{2}.
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