AQA A Level Physics复习笔记2.2.2 Baryons
Baryon Number The baryon number, B, is the number of baryons in an interaction B depends on whether the particle is a baryon, anti-baryon or neither Baryons have a baryon number B = +1 Anti-...
AQA A Level Physics复习笔记2.1.5 Particles, Antiparticles & Photons
Antimatter The universe is made up of matter particles (protons, neutrons, electrons etc.) All matter particles have antimatter counterparts Antimatter particles are identical to their matte...
AQA A Level Physics复习笔记2.1.4 Alpha & Beta Decay
α & β Decay Equations Alpha Decay Alpha decay is common in large, unstable nuclei with too many protons The decay involves a nucleus emitting an alpha particle and decaying into a differ...
AQA A Level Physics复习笔记2.1.3 Strong Nuclear Force
Strong Nuclear Force In the nucleus, there are electrostatic forces between the protons due to their electric charge and gravitational forces due to their mass Comparatively, gravity is a ve...
AQA A Level Physics复习笔记2.1.2 Nucleon & Proton Number
AZX Notation A nuclide is a group of atoms containing the same number of protons and neutrons For example, 5 atoms of oxygen are all the same nuclide but are 5 separate atoms Atomic s...
AQA A Level Physics复习笔记1.2.3 Determining Uncertainties from Graphs
Using Error Bars The uncertainty in a measurement can be shown on a graph as an error bar This bar is drawn above and below the point (or from side to side) and shows the uncertainty in that...
AQA A Level Physics复习笔记1.2.2 Calculating Uncertainties
Uncertainty There is always a degree of uncertainty when measurements are taken; the uncertainty can be thought of as the difference between the actual reading taken (caused by the equipment...
AQA A Level Physics复习笔记1.1.3 Estimating Physical Quantities
Orders of Magnitude A quantity is an “order of magnitude” larger than another quantity if it is about ten times larger Similarly, two orders of magnitude would be 100 times larger, or 102 &n...
AQA A Level Physics复习笔记1.1.2 Powers of Ten
Powers of Ten Physical quantities can span a huge range of values For example, the diameter of an atom is about 10–10 m (0.0000000001 m), whereas the width of a galaxy may be about 1021 m (1...
