Relativistic corrections become necessary when the expression for the kinetic energy
becomes comparable with mc2, where m is the mass of the particle. At what de Broglie wavelength will relativistic corrections become important for an electron?
We know the de Broglie wavelength is given by,
where h is the Planck’s constant, m is the mass and v is the velocity
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(a) When, λ =10nm
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(b) When, λ =10–1nm
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(c) When, λ =10–4nm
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(d) When, λ =10–6nm
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Hence, in cases (c) and (d) velocities are greater than the speed of light and hence relativistic corrections will become important for an electron.