Just finished a list of definitions in physics, syllabus based on Cambridge A-Level (AS).
Specially for those who taking AS. ^.^
1. Scalars – Quantities that have magnitude only.
2. Vectors – Quantities that have magnitude and direction.
3. Systematic Error – Constant deviations of the readings in one direction from the true value.
4. Random Error – Scatter of readings about a mean value.
5. Precision – Degree of agreement among a series of measurements of the same quantity.
6. Accuracy – Degree of agreement between the experimental result and true value.
7. Displacement – Straight line distance and direction of on object from a fixed point.
8. Speed – Distance travelled per unit time.
9. Velocity – Rate of change of displacement with respect to time.
10. Acceleration – Rate of change of velocity with respect to time.
11. Newton’s Law of Motion – 1st – A body remains at rest or continue to move in a straight line with a uniform velocity unless net external force is applied.
2nd – A body on which a force is acting experiences an acceleration in the direction of the force, proportional to the force and inversely proportional to the mass.
- Time rate of change of momentum is proportional to the force producing it, and the changes takes place in the same direction as the force.
3rd – The forces of action and reaction between interacting bodies are equal in magnitude, opposite in directions and collinear.
12. Mass – Measure of its inertia and resistance to acceleration upon the application of force.
13. Weight – Force exerted on a body by gravitational attraction of Earth.
14. Linear Momentum – Product of mass and velocity.
15. Principle of Conservation of Momentum – When objects of a system interacts, their total momentum before impact is equal to their total momentum after impact, if no net external force applied.
16. Perfect elastic Collision – Total kinetic energy of two colliding bodies is conserved.
17. Gravitational Field – A region of space within which a gravitational force is experienced by another mass.
18. Electric Field – A region of space which an electric force is experienced by another charge.
19. Upthrust – Buoyant force exerted by a fluid on the body when the body is immersed in fluid.
20. Frictional force – Resistance to the relative motion between two solid surfaces in contact.
21. Viscous Force – Resistance to the relative motion through the fluid.
22. Centre of Gravity – The point at which the weight of the body appears to act.
23. Couple – Pair of forces, equal in magnitude but opposite direction, which tends to produce rotation.
24. Torque – Product of one of the couple and the perpendicular distance between their lines of action.
25. Moment – Product of the force and the perpendicular distance between the line of action and pivot.
26. Work –Done when force moves its points of application in the direction of the force.
27. Gravitational Potential Energy – Capacity of doing work by virtue of its position.
28. Elastic Potential Energy – Energy stored in the body by virtue of its elastic deformation.
29. Internal Energy – Capacity for doing work by virtue of the state of a system.
30. Power – Rate of work done per unit time.
31. Density – Mass per unit volume.
32. Pressure – Normal force per unit area.
33. Wave Motion – Propagation of disturbances from one region to another.
34. Displacement – Distance of the particle from its equilibrium position and the associated direction.
35. Amplitude – Maximum magnitude of displacement.
36. Period – The number of complete oscillations per unit time made by a point in the wave.
37. Wavelength – The distance between 2 consecutive points in the wave that are in phase.
38. Speed – The distance travelled by any part of waveform per unit time.
39. Phase Difference – The difference in the stages of their oscillations cycle expressed in term of angle.
40. Polarisation – Process by which a wave’s oscillations are made to occur in one plane only.
41. Principle of Superposition – When two waves are superimposed in space, the resultant displacement at any point of space and time is the vector sum of all individual displacement at that point and time.
42. Diffraction – Waves bending round the edges of gaps or objects, spreading into regions where a shadow might be expected.
43. Interference – The result of superposing 2 or more waves.
44. Coherence – Two waves with constant phase difference.
45. Electric Field Strength – Electric force per unit positive charge.
46. Electric Current – The rate of flow of charged particle with respect to time.
47. Charge – A quantity of electricity.
48. Coulomb – The quantity of electricity passing a given point when a current of one ampere is maintained for one second.
49. Potential Difference –The amount of electrical energy converted into other forms of energy per unit charge moved across.
- The power dissipated per unit current.
50. Volt – Joule per coulomb.
51. Resistance – Ratio of the potential difference across it to the current flowing through it.
52. Ohm – Volt per ampere.
53. Ohm’s Law – The current flowing in a metallic conductor is proportional to the potential difference, provided that the physical conditions are constant.
54. Electromotive Force (e.m.f.) – The electrical energy converted from other forms of energy per unit charge delivered round a complete circuit.
- The power delivered per unit current.
55. Kirchoff’s Law – 1st – The sum of the current entering a junction equals the sum of the current leaving that junction.
2nd –In each closed loop of an electric circuit, the sum of e.m.f. equals the sum of p.d. across each resistances.
56. Radioactive Decay – The spontaneous and random disintegration of an unstable nucleus into a more stable configuration by emitting alpha-, beta-, and/or ganma-radiations, with slight or no change in the mass of nucleus.
57. Spontaneous – The decay is independent from external conditions.
58. Random – Constant probability of nucleus decay and unpredictable.
