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9. Ray optics abd optical instruments — Physics STD 12 Science — Question

CBSE BoardEnglish MediumSTD 12 SciencePhysics9. Ray optics abd optical instruments1 Mark
MCQ
Light from a point source falls on a small area placed perpendicular to the incident light. If the area is rotated about the incident light by an angle of $60^o$, by what fraction will the illuminance change
  • A
    It will be doubled
  • B
    It will be halved
  • ✓
    It will not change
  • D
    It will become one-fourth
✓

Answer

Correct option: C.
It will not change
c
( c)Rotation of area about incident light doesn’t change the inclination of the light ray on the area.

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