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Wave Optics — Physics STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 SciencePhysicsWave Optics1 Mark
Question
For question two statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
  1. Both A and R are true and R is the correct explanation of A.
  2. Both A and R are true but R is NOT the correct explanation of A.
  3. A is true but R is false.
  4. A is false and R is also false.
Assertion (A): When monochromatic light is incident on a surface separating two media, the reflected and refracted light both have the same frequency as the incident frequency.
Reason (R): The frequency of monochromatic light depends on media.
✓

Answer

  1. A is true but R is false.
Explanation:

The reflection and refraction of light occurs on account of interaction of light with the atoms of the surface of separation. These atoms can be regarded as oscillators.

Light incident on the interface forces the atomic oscillators to oscillate with frequency of incident light. As frequency of light emitted by these (charged) oscillators is equal to theirown frequency ofosci Ration, therefore, reflected and refracted light have the same frequency as that of incident light.

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