AQA A Level Physics復習筆記8.3.6 Nuclear Radius Equation
Nuclear Radius Values The radius of some nuclei are shown in the table below: In general, nuclear radii are of the order 10–15?m or 1 fm The nuclear radius,?R, varies with nucleon number,?A?...
AQA A Level Physics復習筆記8.3.5 Closest Approach Estimate
Closest Approach Estimate The Coulomb equation can be used to give an estimate for the radius of a nucleus When the alpha particle reaches its closest approach (to the nucleus), all of its k...
AQA A Level Physics復習筆記8.3.4 Nuclear Radius
Estimating Nuclear Radius Closest Approach Method In the Rutherford scattering experiment, alpha particles are fired at a thin gold foil Some of the alpha particles are found to come straigh...
AQA A Level Physics復習筆記8.3.3 Nuclear Excited States
Nuclear Excited States In the same way that electrons can exist in excited states, nuclei can also exist in?excited states After an unstable nucleus emits an alpha particle, beta particle or...
AQA A Level Physics復習筆記8.3.2 Decay Equations
Changes in N and Z by Radioactive Decay There are four reasons why a nucleus might become unstable, and these determine which decay mode will occur Too many neutrons Decays through?beta-minu...
AQA A Level Physics復習筆記8.3.1 Nuclear Instability
Nuclear Stability Graph The most common elements in the universe all tend to have values of N and Z less than 20 (plus iron which has Z = 26, N = 30) Where: N = number of neutrons Z = number...
AQA A Level Physics復習筆記8.2.4 Applications of Radioactivity
Radioactive Dating The isotope carbon-14 is commonly used in radioactive dating It forms as a result of cosmic rays knocking out neutrons from nuclei, which then collide with nitrogen nuclei...
AQA A Level Physics復習筆記8.2.3 Half-Life
Half-Life Half-life is defined as: The time taken for the initial number of nuclei to halve for a particular isotope This means when a time equal to the half-life has passed, the?activity?of...
AQA A Level Physics復習筆記8.2.2 Exponential Decay
Exponential Decay In radioactive decay, the number of undecayed nuclei falls very rapidly, without ever reaching zero Such a model is known as?exponential decay The graph of number of...
