when a ray of light enters a glass slab from air
Correct answer: D. its wavelength decreases
- A. its wavelength night increases
- B. neither its wavelength nor its frequency changes
- C. its frequency increases
- D. its wavelength decreases
Explanation
When a ray of light enters a denser medium like glass from a less dense medium like air, the following happens:Speed of light decreases: Light travels slower in denser media compared to less dense media.Frequency remains constant: According to the wave equation, the frequency (f) of a wave is related to its speed (v) and wavelength (λ) by the formula: f = v / λ. Since the energy carried by the light wave remains constant, the frequency (f) must remain the same as it enters the glass slab.Wavelength decreases: To maintain a constant frequency (f) as the speed (v) decreases, the wavelength (λ) must also decrease proportionally. This is because λ = v / f.Therefore, when a ray of light enters a glass slab from air, its wavelength decreases.
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About Optics
Light is studied through reflection, refraction, dispersion, interference, diffraction and polarization, linking ray behavior with its wave nature. Questions may involve mirrors, lenses, optical instruments, refractive index and image formation, while geometrical optics deals with rays and wave optics explains effects such as interference and diffraction.
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