Thursday, February 7, 2008

IIT JEE Physics Formula Revision 44. X-Rays

1. K = eV
where K = Kinetic energy of an electron when it hits the target
V = potential difference applied between the target and the filament

2. λ = hc/E

Where
λ = wave length of the X-ray
E = kinteic energy of the electron due to which the X-ray is emitted


3. λmin = hc/eV

λmin = cutoff wavelength below which no X-rays are emitted
V = potential difference applied between the target and the filament

4. Moseley's law

Square root of frequency of X rays = a(Z-b)

√(ν) = a(Z-b)

where
ν = frequency of X-rays
Z = position number of element.
a and b are constants

5. Bragg’s law

2d sin θ = n λ

d = interplanar spacing of the crystal on which X-rays are incident
θ = is the incident angle at which X-rays are strongly reflected.
n = 1,2,3 …
λ = wave length of X-rays

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