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NEETPhysicsDual Nature of Matter

The threshold wavelength for photoelectric emission from a material is 5500 A ∘ . Photoelectrons will be emitted, when this material is illuminated with monochromatic radiation from a A. 75 W infra-red lamp B. 10 W infra-red lamp C. 75 W ultra-violet lamp D. 10 W ultra-violet lamp Choose the correct answer from the options given below :

Options

  1. AB and C only
  2. BA and D only
  3. CC only
  4. DC and D only

Correct answer

D. C and D only

Step-by-step solution

Given here, threshold wavelength λ th = 5500 Å = 550 nm For photoelectric emission, the wavelength of the light should be less than 550 nm . Wavelength of infrared radiation extends from 700 nm - 1 mm and that of ultraviolet radiation is 100 - 400 nm . Since, UV light has less wavelength than 550 nm , so only UV would be able to emit photoelectrons.

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