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NEETPhysicsDual Nature of Matter

The threshold wavelengths for four different metals A, B, C and D are given in the table below: Metal Threshold Wavelength ( _ th ) A 400 nm B 500 nm C 600 nm D 700 nm If a monochromatic light beam of wavelength 550 nm is incident on all of them, which of the metals will show photoelectric emission?

Options

  1. AA and B only
  2. BC only
  3. CA, B, C and D
  4. DC and D only

Correct answer

D. C and D only

Step-by-step solution

For photoelectric emission to occur, the incident wavelength ( ) must be less than or equal to the threshold wavelength ( _ th ) of the metal. Given incident wavelength, = 550 nm . Comparing with the given threshold wavelengths: For metal A: 550 nm > 400 nm (No emission) For metal B: 550 nm > 500 nm (No emission) For metal C: 550 nm For metal D: 550 nm Therefore, only metals C and D will show photoelectric emission. Answer: C and D only

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