What this topic covers
Turning points in physics (A-level only) has 3 subtopics:
- The discovery of the electron (A-level only)
- Wave-particle duality (A-level only)
- Special relativity (A-level only)
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A Level AQA Physics · Topic 12 of 13
Turning points in physics (A-level only) – A Level AQA Physics revision notes
Choose a subtopic. Turning points in physics (A-level only) covers The discovery of the electron (A-level only), Wave-particle duality (A-level only), and Special relativity (A-level only) in A Level AQA Physics. 21 lessons in 3 subtopics.
Revise Turning points in physics (A-level only) for A Level AQA Physics, including The discovery of the electron (A-level only).
21
Lessons
3
Subtopics
Turning points in physics (A-level only) lessons by subtopic
21 lessons, grouped by subtopic.
The discovery of the electron (A-level only)
- Cathode Ray Production: Explore the production of cathode rays using a discharge tube.
- Thermionic Emission and Electron Acceleration: Explore the principle of thermionic emission and calculate the work done on an electron accelerated through a potential difference.
- Millikan's Oil Drop Experiment: Equilibrium and Forces: Explore the conditions for holding a charged oil droplet stationary and derive the equation relating charge, voltage, distance, mass, and gravity. Investigate the motion of a falling oil droplet.
- Stokes' Law and Significance of Millikan's Results: Learn about Stokes' Law and how it's used to calculate the radius of an oil droplet. Understand the significance of Millikan's results and the concept of charge quantization.
- Determining Specific Charge: Learn how to determine the specific charge of an electron and understand Thomson's experiment.
Wave-particle duality (A-level only)
- Young's Double Slits: Unveiling Light's True Nature: Explore Young's double-slit experiment and its revolutionary impact on understanding the nature of light, including the explanation of interference fringes and the historical context of Huygens' wave theory.
- Black-Body Radiation and Planck's Quanta: Explore the ultraviolet catastrophe and how Planck's interpretation of quanta revolutionised physics.
- Einstein's Photoelectric Explanation: Understand the limitations of classical wave theory and how Einstein's explanation of photoelectricity changed our understanding of electromagnetic radiation.
- Electron Microscopes: Anode Voltage & TEM: Explore the anode voltage required for atomic-scale wavelengths and the principles behind Transmission Electron Microscopes (TEM).
- Scanning Tunnelling Microscopes (STM): Understand the principles of operation behind Scanning Tunnelling Microscopes (STM).
- De Broglie's Hypothesis: Explore De Broglie's hypothesis and its implications, including calculations using the equations p=h/λ and λ=h/√(2meV).
- Low-Energy Electron Diffraction: Investigate low-energy electron diffraction experiments and understand how changes in electron speed affect the diffraction pattern.
- Newton's Corpuscular Theory of Light: Explore Newton's corpuscular theory of light and compare it with Huygens' wave theory, focusing on the reasons for the preference of Newton's theory.
Special relativity (A-level only)
- Inertial Frames and the Laws of Physics: Explore inertial frames of reference and understand why physical laws remain consistent within them.
- Einstein's Postulates: The Foundation of Special Relativity: Delve into the two fundamental postulates of Einstein's theory of special relativity and their implications.
- Understanding Length Contraction: Learn about length contraction in special relativity and apply the formula to calculate the observed length of moving objects.
- Time Dilation: Introduction: Understand proper time, time dilation and the equation relating them.
- Experimental Evidence: Muon Decay: Examine evidence for time dilation through the observation of muon decay.
- Mass-Energy Equivalence and Relativistic Kinetic Energy: Explore Einstein's famous equation E=mc^2 and its implications, along with the relativistic kinetic energy equation. Understand the relationship between mass and energy, and how kinetic energy varies with speed according to special relativity.
- Bertozzi's Experiment: Evidence for Relativistic Kinetic Energy: Investigate Bertozzi's experiment, a direct confirmation of the relativistic kinetic energy equation. Analyse how the experiment provides evidence for the variation of kinetic energy with speed, validating the predictions of special relativity.
- Michelson-Morley Experiment: Unveiling the Invariance of Light: Explore the Michelson-Morley experiment, its purpose in detecting absolute motion, and its surprising outcome that led to the concept of the invariance of the speed of light.
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Frequently asked questions
What is Turning points in physics (A-level only)?
Turning points in physics (A-level only) covers The discovery of the electron (A-level only), Wave-particle duality (A-level only), and Special relativity (A-level only) in A Level AQA Physics. 21 lessons in 3 subtopics.
What does E = mc² mean?
E = mc² means mass and energy are equivalent and interconvertible. The Mass-Energy Equivalence and Relativistic Kinetic Energy notes cover this in full.
What is Stokes' law?
Stokes' law gives the viscous drag force on a small sphere moving slowly through a fluid with laminar flow. The Stokes' Law and Significance of Millikan's Results notes cover this in full.
How do you calculate de Broglie wavelength?
De Broglie wavelength is calculated with λ = h/(mv). The De Broglie's Hypothesis notes cover this in full.
What is the Lorentz factor?
The Lorentz factor, γ, is 1 ÷ √(1 − v²/c²), so the time dilation equation becomes t = γt₀. The Time Dilation: Introduction notes cover this in full.
What was the Michelson-Morley experiment?
The Michelson-Morley experiment of 1887 used an interferometer to try to detect Earth's motion through the aether which should have changed the measured speed of light in different directions. The Michelson-Morley Experiment: Unveiling the Invariance of Light notes cover this in full.
What is Huygens' principle?
Huygens' principle states that each point on a wavefront acts as a secondary source of new wavelets, and the envelope of these wavelets forms the next wavefront. The Newton's Corpuscular Theory of Light notes cover this in full.
What is the ultraviolet catastrophe?
The ultraviolet catastrophe is the prediction of classical wave theory, the Rayleigh-Jeans law, that a black-body should emit ever-increasing intensity at higher frequencies, giving an infinite total radiated power. The Black-Body Radiation and Planck's Quanta notes cover this in full.
What is an inertial frame of reference?
An inertial frame of reference is a frame that is not accelerating: one that moves at constant velocity, including being at rest. The Inertial Frames and the Laws of Physics notes cover this in full.