Question 32. Analyse the evidence from at least three such experiments about the interaction between light and matter.
The examiners have made this question way harder than they imagined. If a scientist did not do experiments, then their work should not be mentioned. For example, Einstein did no experiments on the interaction of light with matter. He analysed the experiments of other scientists. For example, most of Einstein's ground-breaking work on the photoelectric effect relied on the experiments of Philipp Lenard. It was Lenard who gathered all the data, which then Einstein interpreted in a new way, but Einstein didn't do the experiments.
Here is my list of top experiments involving light and matter:
(1) Isaac Newton - showed that white light could be split by a prism, and that if the colours were re-combined you could re-create white light.
(2) Francesco Grimaldi - discovered that when light passed through two narrow apertures, that the light spread out after the second aperture, a phenomenon he called "diffraction" and he correctly deduced that the light was bending around the aperture, and this indicated light was a wave.
(3) Jean Foucault - measured the speed of light in water, showed that it was slower than the speed of light in air, and thereby disproved Newton's corpuscular theory of light.
(4) Joseph Fraunhofer - discovered dark absorption bands in the spectrum of the Sun, hypothesised that there were new elements.
(5) Gustav Kirchhoff - discovered that hot elements gave off a line spectrum, constructed the first spectroscope and then discovered dozens of new elements by spectroscopy. Also analysed the blackbody heat radiation spectrum.
(6) Philipp Lenard - showed that photoelectrons displayed a cut-off frequency for emission that depended on the identity of the metallic surface. Showed that the kinetic energy of photoelectrons was not increased by increasing the intensity of light, only by reducing the wavelength (or increasing the frequency) of the light.