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## Homework Statement

In order to study the atomic nucleus, we would like to observe the diffraction of particles whose de Broglie wavelength is about the same size as the nuclear diameter, ~14 fm for a heavy nucleus such as lead. What kinetic energy should we use if the diffracted particles are

a) electrons

b) neutrons

c) alpha particles (m = 4 u)

## Homework Equations

[itex]p = \frac{h}{\lambda}[/itex]

[itex]E^{2}=(pc)^{2}+(mc^{2})^{2}[/itex]

## The Attempt at a Solution

Am I supposed to use these equations for each part?

[itex]pc = \frac{hc}{\lambda}[/itex]

[itex]E^{2}=(pc)^{2}+(mc^{2})^{2}[/itex]

[itex]K=E-mc^{2}[/itex]

However, for c) [itex]E \approx mc^{2}[/itex] so we should use a non-relativistic formula [itex]K=\frac{p^{2}}{2m}=\frac{(pc)^{2}}{2mc^2}[/itex] instead.

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