AQA_2024: A-level Physics - Paper 3 Section B Medical Physics. (Merged Question Paper and Marking Scheme)

AQA_2024: A-level Physics - Paper 3 Section B Medical Physics. (Merged Question Paper and Marking Scheme) Please write clearly in block capitals. Centre number Surname Forename(s) Candidate number Candidate signatu re A-level PHYSICS Paper 3 Section B I declare this is my own work. Medical physics Monday 17 June 2024 Materials For this paper you must have:  a pencil and a ruler  a scientific calculator  a Data and Formulae Booklet  a protractor. Instructions Morning Time allowed: The total time for both sections of this paper is 2 hours. You are advised to spend approximately 50 minutes on this section. For Examiner’s Use  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.  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 35.  You are expected to use a scientific calculator where appropriate.  A Data and Formulae Booklet is provided as a loose insert.  Question Mark 1 2 3 4 IB/M/Jun24/E8 5 TOTAL For A-Level Physics Paper 3 Section B: Medical Physics, focus on the following key areas: 1. Medical Imaging:  X-rays: Understand the principles behind X-ray imaging, including how X-rays are produced, how they interact with matter, and how they are used to form images. Study the concept of radiographic contrast and the penetration of X-rays through different tissues.  CT Scans: Learn how computed tomography (CT) works by taking multiple X-ray images from different angles and using computer processing to create cross-sectional images of the body.  MRI (Magnetic Resonance Imaging): Understand the principles of MRI, how it uses strong magnetic fields and radio waves to produce detailed images of organs and tissues. Study the concept of spin and resonance in hydrogen nuclei, and how it contributes to the imaging process.  Ultrasound: Study the use of ultrasound in medical imaging, how high-frequency sound waves are emitted and reflected off tissues to produce an image. Understand concepts like echoes, sonograms, and the advantages of ultrasound in soft tissue imaging.  Positron Emission Tomography (PET): Understand how PET scans use positron-emitting isotopes to create images of metabolic processes in the body, and how they are used in cancer detection and other diseases. 2. Radiation Therapy:  Radiotherapy: Learn how ionizing radiation (such as X-rays, gamma rays, or proton beams) is used to treat cancer by targeting and destroying cancerous cells. Understand dosage and how it is calculated to balance treatment effectiveness with minimal damage to surrounding healthy tissue.  Brachytherapy: Study the concept of brachytherapy, where radioactive sources are placed inside or very close to the tumor, and how it differs from external radiotherapy. 3. Nuclear Medicine:  Radioactive Tracers: Understand how radioactive tracers are used in diagnostic procedures, such as in SPECT (Single Photon Emission Computed Tomography) and PET. These tracers emit gamma radiation, which can be detected to show the functioning of organs.  Half-Life and Dosage: Be able to calculate the half-life of radioactive materials used in medical applications and understand how this impacts the timing of treatments and diagnostics. 4. Ionizing and Non-Ionizing Radiation:  Ionizing Radiation: Study the properties of ionizing radiation (X-rays, gamma rays, alpha, and beta particles), how it can damage tissues and DNA, and how radiation dose is measured in sieverts (Sv).  Non-Ionizing Radiation: Understand the medical use of non-ionizing radiation, such as in MRI and ultrasound, and why it is considered safer than ionizing radiation. 7408/3BB 2 Do not write outside the box Section B IB/M/Jun24/7408/3BB Answer all questions in this section. . A human eye has a far point of 6.0 m. State the name of this defect of vision. [1 mark] . Calculate the power of the correcting lens required for this eye. [2 marks] power = D . An eye with astigmatism requires the following prescription: −4.00 –0.75 ×30 Which row identifies the meaning of each number? Tick () one box. [1 mark] −4.00 −0.75 ×30 axis cylinder spherical cylinder axis spherical spherical cylinder axis cylinder spherical axis 4 1 2 3 1 0 1 0 1 0 3 Do not write outside the box IB/M/Jun24/7408/3BB 0 2 . 1 A stadium is full of spectators. The peak sound-intensity level at the centre of the stadium is 110 dB. On another occasion the number of spectators in the stadium is reduced by 60%. Estimate the peak sound-intensity level at the centre of the stadium. You should assume that on both occasions:  the sound intensity produced by each spectator is the same  the spectators are distributed evenly around the stadium. [4 marks] peak sound-intensity level = dB 0 2 . 2 Describe the changes to a person’s hearing that may result from prolonged exposure to sound at 110 dB. [2 marks] Turn over ► 6 4 Do not write outside the box IB/M/Jun24/7408/3BB 0 3 . 1 Name the two types of optical fibre bundle used in an endoscope. Go on to discuss whether the optical fibres in either of these bundle