(a) A beam of electrons each of de Broglie wavelength 2.4×10−15 m is incident on a thin film of silicon-30 (1430Si). The variation in the electron intensity of the beam with scattering angle is shown.
(a)(i) Use the graph to show that the nuclear radius of silicon-30 is about 4 fm. [3]
(a)(ii) Estimate, using the result from (a)(i), the nuclear radius of thorium-232 (90232Th). [2]
(a)(iii) Suggest one reason why a beam of electrons is better for investigating the size of a nucleus than a beam of alpha particles of the same energy. [1]
(a)(iv) Outline why deviations from Rutherford scattering are observed when high-energy alpha particles are incident on nuclei. [2]
(b) Silicon-30 (1430Si) can be formed from phosphorus-30 (1530P) by a process of beta-plus decay.
(b)(i) Write down the nuclear equation that represents this reaction. [2]
(b)(ii) Sketch the Feynman diagram that represents this reaction. The diagram has been started for you. [3]
(b)(iii) Energy is transferred to a hadron in an attempt to separate its quarks. Describe the implications of quark confinement for this situation. [2]
(c) The Standard Model was accepted by many scientists before the observation of the Higgs boson was made. Outline why it is important to continue research into a topic once a scientific model has been accepted by the scientific community. [1]