Wavelength of X-rays falling at glancing angle of 30? on a crystal with atmic spacing 2 x 10^-10 for the fist order diffraction is________________?
Correct answer: B. 2 x 10^-10 m
- A. 4 x 10^-10 m
- B. 2 x 10^-10 m
- C. 0.02 x 10^-10m
- D. 20 x 10^-10m
Explanation
Using Bragg's law, 2d sin θ = nλ. For d = 2 x 10^-10 m, θ = 30° and first order n = 1, λ = 2 x 2 x 10^-10 m x sin 30° / 1 = 2 x 10^-10 m. Students may choose a by omitting the sin 30° factor and obtaining 4 x 10^-10 m.
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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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