OCR A Level Physics B (Advancing Physics)
OCR A Level Physics B Module 3: Physics in Action Exam Questions
Free OCR A Level Physics B exam questions for Module 3: Physics in Action, with a mark scheme for every pack. Covers lenses and imaging, digitising and sampling signals, information and bits, sensing circuits, conductance, and stress, strain and designer materials.
Module 3: Physics in Action exam questions
1 question pack of real past exam questions, each with its mark scheme. Do not stop after a few: answer as many as you can without notes, then mark every answer with the mark scheme. The more questions you do, the more quickly you will spot how examiners ask about each idea.
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A-Level Physics Flashcards for 2027 Onwards
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About OCR A Level Physics B Module 3: Physics in Action
Module 3 of OCR A Level Physics B (Advancing Physics), Physics in Action, looks at the physics behind communication technology and materials. The communication part covers imaging with lenses, storing and sending images and signals digitally, sampling and resolution, and electrical sensing with potential dividers. The designer materials part covers stress, strain and the Young modulus and how microstructure explains material behaviour. It reflects the course's focus on physics in real applications. Examiners test lens equations with the Cartesian convention, bits and sampling rate calculations, potential divider design, conductance, and interpreting stress-strain graphs for metals, ceramics and polymers.
What you need to know
- Imaging Lenses change the curvature of wavefronts; lens power in dioptres = 1 / f; the lens equation 1/v = 1/u + 1/f using the Cartesian sign convention; and linear magnification = image size / object size = v / u.
- Digital signals Sampling must be at least twice the highest frequency to reconstruct a signal; b bits give 2^b levels; bit rate = samples per second x bits per sample; noise and resolution limit the information carried.
- Sensing Potential dividers with sensors such as thermistors and LDRs, sensitivity and resolution of sensors, and EMF and internal resistance.
- Electrical properties Conductance G = I / V = 1 / R, conductances in parallel add, conductivity and resistivity of materials, and current as flow of charge.
- Designer materials Stress, strain, the Young modulus, breaking stress, toughness, hardness and brittleness, and how grain structure, dislocations and bonding explain the behaviour of metals, ceramics and polymers.
Common mistakes in Module 3: Physics in Action
- Forgetting the Cartesian sign convention with lenses. Real objects have negative u, so take care with signs in 1/v = 1/u + 1/f.
- Thinking sampling at the highest signal frequency is enough. The sampling rate must be at least twice the highest frequency to avoid losing information.
- Adding conductances in series. Conductances add in parallel; in series it is resistances that add.
- Saying brittle materials have a low Young modulus. Brittleness means fracture without plastic deformation; ceramics are brittle but very stiff.
- Mixing up the number of levels and the number of bits. 8 bits give 2^8 = 256 levels, not 8 levels.
Try three Module 3: Physics in Action exam-style questions
1. A lens of power 20 D forms an image of an object placed 0.20 m in front of it. Using 1/v = 1/u + 1/f with u = -0.20 m, calculate the image distance. (2 marks)
Show the mark scheme answer
1/v = 1/(-0.20) + 20 = -5 + 20 = 15 m-1; v = 1/15 = 0.067 m.
2. An audio signal is sampled 44 100 times per second using 16 bits per sample. Calculate the bit rate. (2 marks)
Show the mark scheme answer
44 100 x 16; = 705 600 bit s-1 (about 7.1 x 10^5 bit s-1).
3. Explain why metals are ductile while ceramics are brittle. (3 marks)
Show the mark scheme answer
Metals have mobile dislocations that can move through the crystal lattice, allowing planes to slip and plastic deformation; ceramics have rigid ionic or covalent bonding so dislocations cannot move; cracks propagate easily causing brittle fracture.
Module 3: Physics in Action FAQs
What does OCR A Level Physics B Module 3: Physics in Action cover?
Communication (imaging, signalling and sensing) and designer materials (stress, strain and microstructure).
Which equations do I need for Physics in Action?
Lens power = 1 / f, 1/v = 1/u + 1/f, magnification v / u, number of levels 2^b, bit rate, conductance G = 1/R, stress, strain and the Young modulus.
How do I revise designer materials?
Learn the stress-strain graph shapes for metals, ceramics and polymers and be able to explain each using the material's microstructure and bonding.
