CAIE A-Level Physics 22.3.4 Using λ = h/p

Practise calculating de Broglie wavelength with lambda = h/p, rearranging the relationship and predicting how particle momentum changes diffraction behaviour.

Exam points

calculate particle wavelength using lambda = h/p
rearrange the de Broglie relationship and interpret momentum and wavelength

[Maximum number: 2]

Calculate the speed of an electron having a de Broglie wavelength equal to the wavelength in (b)(ii).

speed =

$\mathrm{ms}^{-1}$

$\lambda=h / m v$

\begin{aligned} v & =\left(6.63 \times 10^{-34}\right) /\left(9.11 \times 10^{-31} \times 4.35 \times 10^{-7}\right) \\ & =1.67 \times 10^{3} \mathrm{~ms}^{-1} \end{aligned}

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22.3.4—Λ = h / p question 1