Materials | Edexcel A-Level Physics (9PH0)
Materials
- 101 questions
- 12 subtopics
- Paper 2: Advanced Physics II
- Paper 2 and Paper 3
Paper 2 content covering density and upthrust, viscous drag and Stokes' law, and the mechanical behaviour of solids: Hooke's law, stress, strain and the Young modulus, force-extension and stress-strain graphs, and the energy stored in a stretched sample.
Three core practicals sit inside it.
Sample questions from Materials
Answer each one closed book first, then open the answer.
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Density and how it is measured
A density is quoted as 1 g cm⁻³. What is this in SI units?
Show the answer
It is 1 × 10³ kg m⁻³. -
Upthrust and Archimedes' principle
Under what condition does an object float in a fluid?
Show the answer
It floats when it can displace fluid whose weight equals its own weight, which happens when its average density is less than the density of the fluid. -
Viscosity, laminar flow and Stokes' law
What is the SI unit of viscosity?
Show the answer
Viscosity is measured in pascal seconds, Pa s, which is the same as N s m⁻². -
Terminal velocity of a sphere falling through a liquid
Two ball bearings of the same material are dropped into the same oil, one having twice the radius of the other. What is the ratio of their terminal velocities?
Show the answer
Since terminal velocity is proportional to r², the larger ball reaches four times the terminal velocity of the smaller one. -
Hooke's law, stress and strain
What does a large value of k tell you about a spring?
Show the answer
The spring is stiff, so a large force is needed to produce a given extension. -
The Young modulus and calculations with it
A cable of cross-sectional area 2.0 × 10⁻⁵ m² supports a load of 500 N. What is the tensile stress in it?
Show the answer
Stress = F/A = 500/(2.0 × 10⁻⁵) = 2.5 × 10⁷ Pa. -
Force-extension graphs, elastic and plastic deformation
What is meant by the elastic limit?
Show the answer
It is the maximum load a sample can carry and still return to its original length when the load is removed. -
Stress-strain graphs, ductile and brittle materials
Why is a stress-strain graph more useful than a force-extension graph when comparing two materials?
Show the answer
Stress and strain do not depend on the dimensions of the sample tested, so the graph describes the material itself rather than one particular specimen.
The 12 subtopics
One subtopic is one session. Work down the list.
| Subtopic | What it covers | Questions |
|---|---|---|
| Density and how it is measured | Recall questions on the definition and unit of density, converting from g cm⁻³, and measuring the density of an irregular solid and of a liquid. | 8 |
| Upthrust and Archimedes' principle | Recall questions on what upthrust is, Archimedes' principle, why a pressure difference produces it, and writing it in terms of the fluid density and volume displaced. | 8 |
| Floating, sinking and upthrust calculations | Recall questions on the condition for floating, the fraction submerged, why a steel ship floats, and finding a volume from apparent loss of weight. | 8 |
| Viscosity, laminar flow and Stokes' law | Recall questions on what viscosity measures, Stokes' law and the conditions under which it holds, laminar and turbulent flow, and the effect of temperature. | 8 |
| Terminal velocity of a sphere falling through a liquid | Recall questions on the three forces acting, the condition at terminal velocity, the expression that follows, and how terminal velocity depends on radius. | 8 |
| Measuring viscosity by the falling-ball method | Recall questions on the falling-ball experiment, why the markers are placed below the surface, checking terminal velocity has been reached, and the main uncertainties. | 9 |
| Hooke's law, stress and strain | Recall questions on the statement of Hooke's law, what the spring constant means, tensile and compressive stress, and why strain has no unit. | 8 |
| The Young modulus and calculations with it | Recall questions on the definition and unit of the Young modulus, what a large value means, and how it differs from the stiffness of one sample. | 8 |
| Determining the Young modulus of a wire | Recall questions on the wire experiment, why a long thin wire is chosen, the small initial load, the safety precautions, and which measurement dominates the uncertainty. | 9 |
| Force-extension graphs, elastic and plastic deformation | Recall questions on the limit of proportionality and the elastic limit, elastic against plastic deformation, the yield point, and loading and unloading curves. | 9 |
| Stress-strain graphs, ductile and brittle materials | Recall questions on the shape of a ductile metal's graph, breaking stress, what the gradient gives, and how a brittle material differs. | 8 |
| Elastic strain energy | Recall questions on the energy stored in a stretched sample, why the factor of a half appears, which area of a graph represents it, and estimating it from a curve. | 10 |
How the guide is worked
Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.
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Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
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Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
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Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.
Read the full method, the return schedule and the research behind it.
Nearby topics
Edexcel A-Level Physics Active Recall Guide
Every topic, not just this one. 1,616 questions with their answers.