A beam of electrons is accelerated through a potential difference of and then allowed…

PHYSICS · Multi-part · A Level · Physics · Particles and radiation · Particles and radiation

Problem

A beam of electrons is accelerated through a potential difference of

54\,\text{V}

and then allowed to fall on a single crystal of nickel whose interplanar spacing is

d=0.091\,\text{nm}

. (i) Calculate the de Broglie wavelength of the electrons. \newline Constants:

h=6.626\times10^{-34}\,\text{J\,s}

m_e=9.11\times10^{-31}\,\text{kg}

e=1.6\times10^{-19}\,\text{C}

. (ii) Using the first-order condition for constructive scattering from the crystal, determine the glancing angle

\theta

(measured from the crystal planes) at which the principal intensity maximum is observed.