AQA GCSE Combined Science: Trilogy Physics Paper 2 (Foundation), November 2020: Question 3
9 marks · Low Demand difficulty · Short Answer
Identify properties, hazards, and communication uses of electromagnetic waves, including X-rays, gamma rays, microwaves, and visible light.
Practise this questionQuestion
Question text
03 X-rays and gamma rays are types of electromagnetic waves.
X-rays are used for medical imaging.
03.1 Which substance will not absorb X-rays?
[1 mark]
Tick ( ) one box.
Bone Metal Skin
Table 1 shows the effect of exposure to different doses of radiation.
Table 1
Dose in mSv Effect on the human body
100 slightly increased risk of cancer
1000 5% increased risk of cancer
5000 high risk of death
03.2 During one X-ray a person receives a dose of 0.100 mSv
Why is this dose unlikely to harm the person?
[1 mark]
03.3 A doctor takes an X-ray photograph of a person.
When taking the X-ray photograph, the doctor stands behind a screen.
Suggest why.
[1 mark]
03.4 Which of the following are gamma rays used for?
[1 mark]
*10* Tick ( ) one box.
Cooking food
Energy-efficient lamps
Sterilising medical equipment
03.5 Why are gamma rays and X-rays harmful to humans?
[1 mark]
Tick ( ) one box.
They are ionising
They are radioactive
They travel at the speed of light
03.6 Electromagnetic waves are also used in communications.
Describe how microwaves and visible light are used in communications.
[4 marks]
Microwaves
Visible light
Mark scheme
Show the mark scheme
AO /
Question Answers Extra information Mark
Spec. Ref.
03.1 skin 1 AO1
6.6.2.4
03.2 dose is much lower than even allow much less than 100 mSv 1 AO3
slight increased risk of cancer 6.6.2.3
dose
03.3 to reduce the dose of radiation allow reduce the risk 1 AO3
(they are exposed to) 6.6.2.3
03.4 sterilising medical equipment 1 AO1
6.6.2.3
03.5 they are ionising 1 AO1
6.6.2.3
03.6 microwaves AO1
6.6.2.4
data is transmitted / detected allow signal / information for 1
data
by (mobile) phone / WiFi / allow bluetooth 1
satellite
visible light
example of device / system 1
description of how light is used 1
e.g. the internet transfers
information via visible light in
fibre optics
e.g. image produced / seen on a
TV / mobile phone
allow any sensible suggestion
for visible light, but the two
marks must be linked
Total 9
How to answer it
Electromagnetic Waves: Uses, Hazards, and Communications
What this question tests
This question assesses your understanding of the electromagnetic (EM) spectrum from AQA GCSE Combined Science (Trilogy) Physics:
- Absorption and penetration of X-rays: how dense tissues absorb X-rays while soft tissues transmit them.
- Radiation dose evaluation: comparing given numerical doses (in mSv) to known threshold risks.
- Radiation safety precautions: methods to minimize ionizing radiation exposure for operators.
- Uses and hazards: gamma rays for sterilization, ionizing radiation risks (DNA damage/cancer).
- Wave communications: specific uses of microwaves (satellite, mobile networks) and visible light (fiber optics, displays).
Transmission and Absorption of X-rays
Identifying which tissue transmits X-rays
✅ Correct Answer
Skin
💡 Key Knowledge
X-rays pass easily through soft, low-density tissues like skin and flesh (they are transmitted, not absorbed), but are absorbed by dense materials such as bone and metal.
❌ Common Errors
Misreading the word "not" in the question stem and accidentally ticking Bone or Metal.
Evaluating Radiation Dose
Interpreting data from Table 1
✅ Correct Answer
The dose ( 0.100 mSv ) is much lower than the lowest dose shown in Table 1 ( 100 mSv ) that causes a slight increase in cancer risk.
🧠 Exam Technique
Whenever you are given a data table, quote or compare directly to values from the table. Do not just say "it's a small dose" — state that 0.100 mSv is significantly lower than 100 mSv .
❌ Common Errors
Stating that the radiation has "no risk at all" or failing to reference the threshold value from Table 1.
Doctor Safety Precautions
Explaining why radiographers stand behind screens
✅ Correct Answer
- To reduce the radiation dose they receive.
- Also accepted: To reduce the risk (of cell damage or cancer) from repeated exposure.
💡 Key Knowledge
Patients only have an X-ray occasionally, but radiographers perform many every day. Repeated exposure leads to a high cumulative dose, so lead screens or leaving the room is necessary to absorb stray X-rays.
🧠 Exam Technique
Always use the scientific terms "dose" and "risk". Avoid vague phrases like "to stay safe" or "so they don't get hurt".
Uses of Gamma Rays
Selecting the correct medical/industrial application
✅ Correct Answer
Sterilising medical equipment
💡 Key Knowledge
Gamma rays can kill bacteria and viruses on plastic syringes and surgical instruments without heating or melting them.
- Cooking food → Microwaves / Infrared
- Energy-efficient lamps → Ultraviolet (fluorescence)
Hazards of High-Frequency EM Waves
Why X-rays and gamma rays are harmful
✅ Correct Answer
They are ionising
💡 Key Knowledge
Ionisation means having enough energy to remove electrons from atoms. In living cells, this damages DNA molecules, which can cause gene mutations and lead to cancerous tumor growth.
❌ Common Errors
Confusing ionising with radioactive. Waves themselves are not radioactive; unstable atomic nuclei are radioactive and can emit ionizing radiation.
Communications: Microwaves & Visible Light
Describing applications in data transmission
✅ Correct Answer Structure
Microwaves (2 marks):
- Mark 1: Data, signals, or information are transmitted or detected... [1]
- Mark 2: ...by mobile phones, Wi-Fi, satellites, or Bluetooth. [1]
Visible light (2 marks):
- Mark 3: Name of system: optical fibres (fibre optics) / digital screens. [1]
- Mark 4: How light is used: transmitting broadband data via total internal reflection / pulses of light, or displaying images/text on a TV/phone screen. [1]
🧠 Exam Technique
Notice the question says "describe how" and awards 4 marks. You must split your answer into 2 marks for microwaves and 2 marks for visible light:
- State the device or medium.
- State what is happening to the information/signal.
❌ Common Errors
- Writing about cooking food for microwaves — the question specifically specifies communications!
- Saying visible light is "used to see" without connecting it to a communication system like fiber optics or screens.
- Providing standalone examples without explaining how data/signals travel.
Topics
Physics · P6: Waves
Question and mark scheme from the AQA GCSE Combined Science: Trilogy examination, Physics Paper 2 (Foundation), November 2020. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.