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Class 12
Physics
Wave Optics
nbsp estimate the distance for which ray optics i...

Question:
Estimate the distance for which ray optics is good approximation for an aperture of 4 mm and wavelength 400 nm.

Answer:

Fresnel’s distance (Z_f ) is the distance for which the ray optics is a good approximation. It is given by the relation, Z_f = a²/λ

Where,

Aperture width, a = 4 mm = 4 ×10 ^-3 m

Wavelength of light, λ = 400 nm = 400 × 10^-9 m

Z_f = (4x10^-3)²/400x10^-9 = 40 m

Therefore, the distance for which the ray optics is a good approximation is 40 m.

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Estimate the distance for which ray optics is good approximation for an aperture of 4 mm and wavelength 400 nm.

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Question: Estimate the distance for which ray optics is good approximation for an aperture of 4 mm and wavelength 400 nm.

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Question:
Estimate the distance for which ray optics is good approximation for an aperture of 4 mm and wavelength 400 nm.