Course

A2 Physics: Quantum and Nuclear Physics (9702)

Name: A2 Physics: Quantum and Nuclear Physics (9702)
Price: 1799 BDT

9702 topics 22 and 23. Some things only come in whole amounts: one photon, one quantized atomic energy level, one decaying nucleus. The foundational quantum core of modern physics.

28 lessons2h 50mEnglish

What you'll learn

Use E = hf and explain the threshold frequency and stopping potential in the photoelectric effect
Read and calculate transition energies and photon wavelengths on an atomic energy-level diagram
Calculate de Broglie wavelength lambda = h / p for matter particles showing wave-particle duality
Compute mass defect Delta m and binding energy per nucleon, explaining nuclear fission and fusion stability
Solve exponential radioactive decay equations using decay constant lambda and half-life t_half

Requirements

AS topic 11, particle physics: the nuclear atom, nucleon and proton number, and antiparticles
AS topic 7: frequency, wavelength and the wave equation, since the photon links them to energy
Standard form and the electronvolt, used on every line of this module
Exponentials and natural logarithms for nuclear decay kinematics

Course content

28 lessons · 2h 50m

22.1-22.4 · Quantum physics

Light delivered in photons of energy hf, the photoelectric measurements the wave model cannot account for, the de Broglie wavelength of a moving particle, and the discrete energy levels that turn a spectrum into a set of lines.

0/13

Light arrives in packets: E = hf

A dim blue beam works and a bright red beam does not. Find what the beam colour sets.

Preview6m 2.

The threshold frequency

Below one frequency nothing is emitted, whatever the intensity and however long you wait.

Preview6m

Why the wave model fails here

A wave model makes three clear predictions about this experiment, and all three are wrong.

The work function

Sodium emits under visible light and platinum needs ultraviolet. One number explains it.

Stopping potential measures the energy

You cannot weigh the kinetic energy of an electron, but you can find the voltage that stops it.

The photoelectric equation as a line

Plot maximum kinetic energy against frequency and the Planck constant is the gradient.

Electrons build an interference pattern

Each electron lands at one point, and thousands of points build a fringe pattern.

The de Broglie wavelength

Faster electrons give tighter fringes, because momentum sets the wavelength.

Electron energy levels are discrete

An electron in an atom takes one of a fixed set of energies and nothing in between.

10.

Line spectra: hf = E1 − E2

Sharp lines, not a smooth band, because only certain photon energies can be produced.

11.

Absorption takes the same energies out

Dark lines sit exactly where the bright lines were. Read a photon energy off the curve.

12.

One exam question, end to end

Eight marks, four parts, no options: photon energy, maximum kinetic energy, then what doubling intensity does.

13.

Quantum physics: quick revision

Reconnect photons, matter waves and energy levels, then repair the intensity-versus-frequency trap.

23.1-23.2 · Nuclear physics

The mass that goes missing when nucleons bind, the curve of binding energy per nucleon that fission and fusion both climb, and the random decay whose average behaviour is the exponential law.

0/13

The parts weigh more than the whole

Weigh four nucleons, then weigh the nucleus they form. The two numbers disagree.

Preview6m 2.

Turning a mass defect into MeV

One atomic mass unit is worth 931.5 MeV. Follow the substitution that gets there.

Preview6m

Binding energy per nucleon

Uranium has the larger total binding energy and iron is the more stable nucleus.

The curve and its peak at iron

One graph, one peak, and two different ways of climbing towards it.

Fission: splitting climbs the curve

Estimate the energy from one fission using the curve alone, before you are told it.

Keeping the chain reaction at k = 1

The Rooppur reactor holds one number steady. Find out which number and why.

Fusion and why it needs a star

Joining light nuclei releases more per nucleon than fission, and is far harder to start.

Decay is random and spontaneous

You cannot say which nucleus decays next, yet the rate for a large sample is reliable.

Activity and the decay constant

Double the undecayed nuclei and the activity doubles. The gradient of that line is λ.

10.

The exponential decay law

Equal time intervals remove equal fractions, never equal numbers.

11.

Half-life

Halve, halve again, and count the steps. The starting amount never changes the answer.

12.

One exam question, end to end

Seven marks, three parts, no options: a decay constant, a number of nuclei, then three half-lives later.

13.

Nuclear physics: quick revision

Reconnect binding energy and radioactive decay, then rehearse mass–energy and half-life reasoning.

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