PHYSICS Paper 1

A-level PHYSICS Paper 1 Materials For this paper you must have: • a pencil and a ruler • a scientific calculator • a Data and Formulae Booklet • a protractor. Instructions • Use black ink or black ball-point pen. • Fill in the boxes at the top of this page. • Answer all questions. • You must answer the questions in the spaces provided. Do not write outside the box around each page or on blank pages. Time allowed: 2 hours • If you need extra space for your answer(s), use the lined pages at the end of this book. Write the question number against your answer(s). • Do all rough work in this book. Cross through any work you do not want to be marked. • Show all your working. Information • The marks for questions are shown in brackets. • The maximum mark for this paper is 85. • You are expected to use a scientific calculator where appropriate. • A Data and Formulae Booklet is provided as a loose insert. * * IB/M/Jun22/E12 7408/1 Section A Answer all questions in this section. Do not write outside the box Two stable isotopes of helium are 4He and 3He. 2 2 . An atom of 4He is produced in a rock that contains uranium. It is produced following 2 the radioactive decay of a 238U atom. The decay also creates an atom of 92 thorium (Th). Write an equation for the decay of 238U. 92 [2 marks] 238U → 92 . A 3He nucleus can be produced by the decay of a tritium nucleus 3H. 2 1 State and explain which exchange particle is responsible for this decay. [2 marks] Do not write outside the box . Before helium was identified, some scientists suggested that the lines of the helium spectrum seen in the absorption spectrum of the Sun were due to the presence of sodium and hydrogen. Discuss, with reference to the lines A to F in Figure 1, the evidence for and against this suggestion. [2 marks] Question 1 continues on the next page Turn over ► . Calculate, in eV, the change in energy level responsible for the spectral line labelled E in Figure 1. Do not write outside the box [3 marks] change in energy level = eV . Explain, with reference to the processes within an atom, the difference between an emission spectrum and an absorption spectrum. [3 marks] Carbon-14 decays into nitrogen-14 with the release of a beta (β−) particle and an antineutrino ( ve ). Do not write outside the box . State the change of quark character in β− decay. [1 mark] . Figure 2 shows the distribution of kinetic energies of β− particles from the decay of carbon-14. Figure 2