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Ray Optics and Optical Instruments — Physics STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 SciencePhysicsRay Optics and Optical Instruments1 Mark
MCQ

Which of the following quantities increase when wavelength is increased? Consider only the magnitudes.

  • A
    The power of a converging lens.
  • B
    The focal length of a converging lens.
  • C
    The power of a diverging lens.
  • D
    The focal length of a diverging lens.
✓

Answer

  1. The focal length of a converging lens.
  1. The focal length of a diverging lens.

Explanation:

The focal length of a lens is inversely proportional to the refractive index of the lens and the refractive index of the lens is inversely proportional to the square of wavelength. Therefore, the focal length is directly dependent on wavelength; it increases when the wavelength is increased.

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