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NEETChemistryStructure of Atom

A metal surface having a threshold wavelength ₀ is irradiated separately by two different monochromatic light sources of wavelengths ₀ 3 and ₀ 4 . The ratio of the maximum kinetic energy of the emitted photoelectrons in the first case to that in the second case is:

Options

  1. A4 : 3
  2. B3 : 4
  3. C3 : 2
  4. D2 : 3

Correct answer

D. 2 : 3

Step-by-step solution

According to Einstein's photoelectric equation: KE = hc - hc ₀ For the first light source ( ₁ = ₀ 3 ): KE₁ = hc ( ₀ 3 ) - hc ₀ = 3hc ₀ - hc ₀ = 2hc ₀ For the second light source ( ₂ = ₀ 4 ): KE₂ = hc ( ₀ 4 ) - hc ₀ = 4hc ₀ - hc ₀ = 3hc ₀ The ratio of their maximum kinetic energies is: KE₁ KE₂ = ( 2hc ₀ ) ( 3hc ₀ ) = 2 3 Thus, the ratio is 2 : 3 . Answer: 2 : 3

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