NCERT Class XII Chapter
Wave Optics
Questions With Solutions
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Question : 9
Total: 21
Light of wavelength 5000 Å falls on a plane reflecting surface. What are the wavelength and frequency of the reflected light? For what angle of incidence is the reflected ray normal to the incident ray?
Solution:
In the reflected light the wavelength and frequency remain the same as that of incident light. Wavelength of reflected light = 5000 Å, frequency of reflected light c = f λ
f =
10 14
when reflected ray is normal to incident ray, ∠i + ∠r = 90°
2∠i = 90° (∴ ∠i = ∠r)
∠i = 45°
For an angle of incidence 45° the reflected ray is normal to incident ray.
f =
when reflected ray is normal to incident ray, ∠i + ∠r = 90°
2∠i = 90° (∴ ∠i = ∠r)
∠i = 45°
For an angle of incidence 45° the reflected ray is normal to incident ray.
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