Thin Film Interference Quiz

10 Questions | Total Attempts: 2202

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Thin Film Interference Quiz

A short quiz on the key concepts in the Thin Film Interference Unit. Just type in your name and start the quiz. Answers to all the questions will be presented at the end of the quiz.


Questions and Answers
  • 1. 
    Different colours are visible when looking perpendicularly on a thin film of soap because 
    • A. 

      The film reflects some of the light

    • B. 

      The film is thin enough so that the refracted ray is close to the reflected ray

    • C. 

      The reflected ray changes phase by λ/2

    • D. 

      All of the above

    • E. 

      None of the Above

  • 2. 
    If you look perpendicularly at the thin glass film and move your head away from the glass film (staying perpendicular to the film), you will notice
    • A. 

      The reflected light becomes brighter and brighter

    • B. 

      The reflected light alternates between dark and bright spots

    • C. 

      The reflected light becomes darker and darker

    • D. 

      There is no reflected light

    • E. 

      None of the Above

  • 3. 
    A lens (n=1.52) is coated witha film of magnesium fluoride (n=1.25). What should be the least thickness of the film in order to minimize reflected light with a wavelength of 550 nm?
    • A. 

      6.0 X 10^-7 m

    • B. 

      1.8 X 10^-6 m

    • C. 

      1.1 X 10^-7 m

    • D. 

      4.8 X 10^-6 m

    • E. 

      None of the Above

  • 4. 
    When light travels from a fast medium to a slower medium, the refracted ray
    • A. 

      Changes phase by λ/2

    • B. 

      Changes phase by λ/3

    • C. 

      Changes phase by 3λ/2

    • D. 

      Changes phase by λ/4

    • E. 

      None of the Above

  • 5. 
    When a thin glass pane is viewed perpendicularly in white light, only bright white and dark spots are visible.
    • A. 

      True

    • B. 

      False

  • 6. 
    A soap film with a thickness of 93 nm has a refractive index of 1.35. When viewed perpendicularly in white light, what wavelength of light is strongly reflected?
    • A. 

      600nm

    • B. 

      483nm

    • C. 

      500nm

    • D. 

      650nm

    • E. 

      None of the Above

  • 7. 
    Interference doesn't occur in thick films because the refracted ray slows down too much
    • A. 

      True

    • B. 

      False

  • 8. 
    The optical path of light in a thickness of glass is larger than the optical path in the same thickness of air.
    • A. 

      True

    • B. 

      False

  • 9. 
    Interference in thin films follows the same mathematical model as Single Slit Diffraction for constructive interference
    • A. 

      True

    • B. 

      False

  • 10. 
    Thin film interference occurs because the film polarizes the reflected light.
    • A. 

      True

    • B. 

      False

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