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MCQ practice · SSC Physics Board questions · Chapter 8: Reflection of Light

Cumilla Board 2021

What is the wavelength of visible light?

Think it through first, then pick an option.

  1. a 400 nm − 500 nm
  2. b 400 nm − 600 nm
  3. c 400 nm − 700 nm
  4. d 500 nm − 700 nm
Answer and explanation

Correct answer: c 400 nm − 700 nm

400 nm (violet) to 700 nm (red): wavelengths in this range are what we see as light.

Why the other options are wrong

  • a 400 nm − 500 nm: This is not the answer: 400 to 500 nm covers only the violet and blue end; reaching red takes 700 nm.
  • b 400 nm − 600 nm: This is not the answer: The range does not stop at 600 nm; orange and red run from 600 to 700 nm.
  • d 500 nm − 700 nm: This is not the answer: The range does not start at 500 nm; violet and blue begin near 400 nm.

More board questions on this topic