Certain Planes of a Crystal of Halite Have a Spacing

question 2

Multiple Choice

Certain planes of a crystal of halite have a spacing of 0.399 nm. The crystal is irradiated by a beam of x-rays. First order constructive interference occurs when the beam makes an angle of 20° with the planes. What is the wavelength of the x-rays?

• A) 0.14 nm
• B) 0.17 nm
• C) 0.21 nm
• D) 0.24 nm
• E) 0.27 nm

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