OCR GCSE Physics B (Twenty First Century)
OCR GCSE Physics B P1 Radiation and Waves Exam Questions
Free OCR GCSE Physics B revision for P1 Radiation and Waves: what you need to know, common mistakes and exam-style questions with answers. Covers the electromagnetic spectrum, ionising radiation, photons, the greenhouse effect and climate change, wave properties, wave speed, reflection, refraction and lenses.
Practise P1 Radiation and Waves with past papers
Once you have learnt this topic, find the P1 Radiation and Waves questions in real OCR GCSE Physics B past papers and mark them with the mark scheme. Doing lots of real questions is the quickest way to learn how examiners ask about each idea.
StemUp mark scheme flashcards
GCSE Physics Triple Science Flashcards for 2027 Onwards
Every answer is written in mark scheme wording, so you learn exactly what examiners give marks for. Then test yourself with the questions on this page.
From £7.99View flashcards
About OCR GCSE Physics B P1 Radiation and Waves
Chapter P1 opens OCR Physics B (Twenty First Century Science) with the radiation and waves that surround us. You study the electromagnetic spectrum, how radiation is emitted, transmitted and absorbed, and why some radiations are ionising and harmful. The physics of the greenhouse effect and evidence for climate change come next, followed by the general behaviour of waves, including transverse and longitudinal waves and the wave equation. Separate physics adds how light and sound interact with materials. P1 links to energy in P2 and radioactivity in P5. Examiners test wave speed calculations, risks and benefits of radiation, and explanations of the greenhouse effect.
What you need to know
- P1.1 The electromagnetic spectrum In order of increasing frequency: radio, microwave, infrared, visible, ultraviolet, X-rays and gamma rays. All travel at the same speed in a vacuum. Radiation is emitted and absorbed in packets of energy called photons, and higher frequency photons carry more energy.
- P1.1 Risks and benefits Ultraviolet, X-rays and gamma rays are ionising and can damage cells and DNA. Microwaves heat materials containing water, and radio waves are used for communication. Sunscreen and ozone reduce ultraviolet exposure.
- P1.2 Climate change The Earth absorbs radiation from the Sun and emits infrared. Greenhouse gases such as carbon dioxide, methane and water vapour absorb infrared and re-emit it, warming the atmosphere. Increased carbon dioxide from burning fossil fuels is linked to rising global temperatures.
- P1.3 Wave behaviour Waves transfer energy without transferring matter. Transverse waves oscillate at right angles to the direction of travel; longitudinal waves such as sound oscillate parallel to it. Wave speed (m/s) = frequency (Hz) x wavelength (m).
- P1.3 Measuring waves Wave speed can be measured using a ripple tank or for sound in air using echoes or two microphones. The period is the time for one complete wave, and frequency = 1 / period.
- P1.4 Light and sound in materials Separate physics only: waves can be reflected, refracted, transmitted or absorbed. Refraction happens because waves change speed in a new medium; convex lenses focus light and colour depends on which wavelengths are reflected or transmitted.
Common mistakes in P1 Radiation and Waves
- Saying all electromagnetic radiation is harmful. Only the high frequency, ionising parts (ultraviolet, X-rays, gamma) damage cells by ionisation; microwaves cause heating.
- Thinking higher frequency waves travel faster. All electromagnetic waves travel at the same speed in a vacuum.
- Explaining the greenhouse effect as gases trapping sunlight or heat being reflected by the ozone layer. Greenhouse gases absorb and re-emit infrared radiation emitted by the Earth.
- Saying sound waves are transverse. Sound is a longitudinal wave with compressions and rarefactions.
- Forgetting unit conversions such as kHz to Hz or cm to m. Convert before using wave speed = frequency x wavelength.
Try three P1 Radiation and Waves exam-style questions
1. A sound wave has a frequency of 500 Hz and a wavelength of 0.68 m. Calculate its speed. (2 marks)
Show the mark scheme answer
Wave speed = frequency x wavelength = 500 x 0.68; = 340 m/s.
2. Explain why ultraviolet radiation is more hazardous to skin than visible light. (2 marks)
Show the mark scheme answer
Ultraviolet has a higher frequency so its photons carry more energy; it is ionising and can damage cells or DNA, which may lead to skin cancer.
3. Explain how carbon dioxide in the atmosphere keeps the Earth warmer than it would otherwise be. (3 marks)
Show the mark scheme answer
The Earth absorbs radiation from the Sun and emits infrared radiation; carbon dioxide absorbs some of this infrared; and re-emits it in all directions, including back towards the Earth, warming the surface and lower atmosphere.
P1 Radiation and Waves FAQs
What does OCR Physics B P1 Radiation and Waves cover?
It covers the electromagnetic spectrum, photons, ionising radiation and its risks, the greenhouse effect and climate change, and the properties of waves including the wave equation. Separate physics adds reflection, refraction and lenses.
Which paper is it examined in?
OCR Physics B has two papers at each tier, Breadth in physics and Depth in physics, and both can assess content from every chapter, so P1 can appear on either paper.
What equations do I need for P1?
Learn wave speed = frequency x wavelength and be confident rearranging it. You should also know that frequency = 1 / period and recall the order of the electromagnetic spectrum.
