(a(i))[1]
State one item of experimental evidence showing the particulate nature of electromagnetic radiation.
(a(ii))[1]
State one piece of experimental evidence for the wave-like nature of matter.
(b(i))[3]
Calculate the de Broglie wavelength $\lambda$ for an alpha-particle travelling at $6.2 \times 10^{7}\,\text{m s}^{-1}$.
(b(ii))[2]
The speed $v$ of the alpha-particle in (b)(i) is then reduced steadily to zero. On Fig. 8.1, sketch how $\lambda$ varies with $v$.
(c)[1]
Suggest an explanation for why people are not seen to diffract as they walk through a doorway.