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hayowazzup
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Homework Statement
A mono-energetic beam are of neutrons is directed perpendiculary at the surface of a metal crystal whose atom are a constant distance 0.1E-10m apart. The scattered beam of neutrons is found to have maximum intensity at an angle of 25degree to the initial direction. What is the energy (in eV) of the neutrons?
Homework Equations
2dsinθ = nλ
E = hc/λ
The Attempt at a Solution
2(0.1E-10)*sin(25) = (1)λ
λ = 8.45E-12 m
E = hc/λ = (6.63E-34)(3E+8)/ 8.45E-12 m = 2.35E-14 J=146890eV
but ans = 45.7eV
Can anyone tell me where goes wrong?
Is that the right equation uses to find the energy of the neutrons?