Course

O Level Physics: Nuclear and Space Physics (5054)

Name: O Level Physics: Nuclear and Space Physics (5054)
Price: 1299 BDT

5054 sections 5 and 6: atomic structure, radioactivity, half-life, radiation safety, the Solar System, stars and the expanding Universe.

72 lessons11h 47mEnglish

What you'll learn

Describe the nuclear atom and the evidence for it, and read nuclide notation
Identify alpha, beta and gamma radiation and balance decay equations
Find half-life from data and curves, and explain how to use radioactive sources safely
Explain day, seasons, Moon phases and orbits, and use v = 2πr/T and light travel time
Describe the life cycle of stars and the evidence for an expanding Universe

Requirements

Powers of ten (standard form)
Basic graph reading and rearranging a formula

Course content

72 lessons · 11h 47m

5.1.1-5.1.2 · The nuclear model of the atom

A tiny positive nucleus with electrons around it. See the evidence from alpha scattering, count protons and neutrons, read nuclide notation and tell isotopes apart.

0/10

The structure of the atom

A positive nucleus in the middle, negative electrons around it, and almost all of it empty space.

Preview10m 2.

Positive and negative ions

Lose an electron and the atom becomes a positive ion; gain one and it becomes negative.

Preview10m

Alpha particle scattering and the nuclear model

Most alpha particles go straight through thin gold foil, but a few bounce back. What must be inside?

12m

Protons, neutrons and electrons: relative charge and mass

The nucleus holds protons and neutrons. Their relative charges are +1 and 0; the electron is −1.

11m

Proton number and nucleon number

Z counts the protons, A counts protons and neutrons, so the neutrons are A − Z.

11m

Nuclide notation

Nucleon number on top, proton number below: read every particle count from one symbol.

12m

Isotopes

Same element, same proton number, different number of neutrons.

10m

The nuclear model of the atom: practice

A timed drill of mixed questions: particles, charges, ions, scattering, nuclide notation and isotopes.

The nuclear model of the atom: exam practice

Exam-style questions with marks, mark schemes and full worked solutions.

15m

10.

The nuclear model of the atom: summary

The key points, the notation and the common mistakes on one screen, with cards to revise from.

5.2.1-5.2.2 · Detection of radioactivity and the three types of emission

Measure background radiation and count rate, correct a reading, then tell alpha, beta and gamma apart by what they are, how they ionise, what stops them and how fields bend them.

0/10

Background radiation

A detector clicks even with no source nearby. The radiation comes from radon, rocks, food and space.

Preview10m 2.

Detecting radiation: count rate

A detector and a counter record each particle. Divide the counts by the time to get the count rate.

Preview10m

Corrected count rate

Take the background away from the reading to find what the source alone gives.

11m

The nature of alpha, beta and gamma

A helium nucleus, a fast electron and a burst of electromagnetic waves, all thrown out of a nucleus at random.

11m

Ionising effect

Alpha knocks electrons off atoms most strongly because it carries the most charge and moves slowly.

11m

Penetrating ability

Paper stops alpha, a few millimetres of aluminium stop beta, and thick lead only reduces gamma.

12m

Deflection in electric and magnetic fields

Alpha and beta bend opposite ways, beta bends much more, and gamma goes straight on.

12m

Detection and the three types of emission: practice

A timed drill of mixed questions: background, count rate, corrected count rate and alpha, beta and gamma.

Detection and the three types of emission: exam practice

Exam-style questions with marks, mark schemes and full worked solutions.

15m

10.

Detection and the three types of emission: summary

The key points, the comparison table and the common mistakes on one screen, with cards to revise from.

5.2.3-5.2.4 · Radioactive decay, fission and fusion

Why some nuclei are unstable, how alpha, beta and gamma change a nucleus, how to balance decay equations, and how splitting heavy nuclei and joining light ones release energy.

0/10

Radioactive decay

An unstable nucleus changes at random, and alpha or beta decay turns it into a different element.

Preview10m 2.

Alpha decay equations

An alpha particle carries away 4 nucleons and 2 protons, so A falls by 4 and Z falls by 2.

Preview11m

Beta decay equations

A neutron turns into a proton and an electron. The electron leaves, so Z rises by 1 and A stays the same.

11m

Gamma emission

Gamma carries away energy only, so neither the nucleon number nor the proton number changes.

11m

Nuclear fission

A heavy nucleus absorbs a neutron and splits into two smaller nuclei, releasing energy and more neutrons.

11m

Chain reactions and nuclear power

The neutrons from one fission can split more nuclei. Control rods keep the chain steady in a reactor.

12m

Nuclear fusion

Two light nuclei join to make a heavier one. The mass falls a little and energy is released, as in the Sun.

11m

Radioactive decay, fission and fusion: practice

A timed drill of mixed questions: decay equations, what each emission changes, fission and fusion.

Radioactive decay, fission and fusion: exam practice

Exam-style questions with marks, mark schemes and full worked solutions.

15m

10.

Radioactive decay, fission and fusion: summary

The key points, the decay rules and the common mistakes on one screen, with cards to revise from.

5.2.5-5.2.6 · Half-life and safety precautions

Find half-life from tables and decay curves, choose the right isotope for a job, and use time, distance and shielding to keep people safe.

0/11

Half-life

Each nucleus decays at random, yet half of a large sample always goes in the same time.

Preview11m 2.

Finding half-life from data

Take the background away first, then find how long the count rate takes to halve.

Preview11m

Finding half-life from a decay curve

The curve levels off at the background, not at zero. Measure halvings above that level.

12m

Uses of radioactivity: smoke alarms and thickness control

Pick the radiation that the job can stop or measure, and a half-life that lasts as long as the job.

11m

Uses of radioactivity: medicine, sterilising and food

Gamma passes through packaging and bodies, so it sterilises equipment, treats food and finds and treats cancer.

11m

Effects of ionising radiation on living things

Ionising radiation can destroy cells or change their DNA, which can lead to cancer.

10m

Moving, using and storing radioactive materials safely

Tongs, a lead-lined box, a locked store and a record of every use keep a school source safe.

10m

Reducing exposure: time, distance and shielding

Spend less time near a source, keep further away and put an absorber in the way.

11m

Half-life and safety: practice

A timed drill of mixed questions: half-life from data and curves, choosing isotopes and safety.

10.

Half-life and safety: exam practice

Exam-style questions with marks, mark schemes and full worked solutions.

15m

11.

Half-life and safety: summary

The key points, the methods and the common mistakes on one screen, with cards to revise from.

6.1.1-6.1.2 · Earth and the Solar System

Day and night, the seasons and the Moon’s phases; orbital speed; what the Solar System contains, how it formed, why planets orbit the Sun and how to read planetary data.

0/13

Day and night: the Earth's rotation

The Earth spins on a tilted axis once in about 24 hours, so the Sun seems to cross the sky.

Preview10m 2.

The seasons: the Earth's orbit and tilt

The Earth goes round the Sun in about 365 days. Its tilt, not its distance, makes the seasons.

Preview10m

The Moon and its phases

The Moon orbits the Earth in about a month, so we see more or less of its sunlit half.

10m

Average orbital speed

One orbit is a circle of length 2πr covered in time T, so v = 2πr/T.

11m

What is in the Solar System

One star, eight planets in order, dwarf planets, asteroids, moons and comets.

10m

Rocky planets and gas giants: the accretion model

Near the hot young Sun only rock and metal could clump together; further out, ice and gas could too.

10m

Gravitational field strength and the Sun's pull

A bigger mass gives a stronger field, and the field weakens with distance. The Sun holds the planets.

11m

Elliptical orbits

Orbits are ellipses with the Sun off-centre. A planet speeds up as it falls closer to the Sun.

11m

How long light takes to travel in space

Light from the Sun takes about 500 seconds to reach us: time = distance ÷ speed of light.

10m

10.

Analysing planetary data

Read a table of distance, orbital time, density, temperature and surface g, and spot the patterns.

12m

11.

Earth and the Solar System: practice

A timed drill of mixed questions: day, seasons, Moon, orbital speed, planets, gravity and light time.

12.

Earth and the Solar System: exam practice

Exam-style questions with marks, mark schemes and full worked solutions.

15m

13.

Earth and the Solar System: summary

The key points, formulas and common mistakes on one screen, with cards to revise from.

6.2.1-6.2.3 · Stars and the Universe

The Sun as a star, galaxies and light-years, how stars are born and die, and how redshift, the CMBR and the Hubble constant show an expanding Universe that began with a Big Bang.

0/12

The Sun as a star

A medium-sized ball of hydrogen and helium, shining in infrared, visible and ultraviolet, powered by fusion.

Preview10m 2.

Galaxies and the Milky Way

Our Sun is one of billions of stars in the Milky Way, one of billions of galaxies.

Preview10m

Light-years

A light-year is a distance: how far light goes in one year, 9.5 × 10¹⁵ m.

10m

How a star forms

Gravity pulls a cloud of gas and dust into a hot protostar, which becomes stable when the forces balance.

11m

The life cycle of a star like the Sun

When its hydrogen is used up, a star like the Sun swells into a red giant, then leaves a white dwarf.

11m

The life cycle of a massive star

A red supergiant explodes as a supernova and leaves a neutron star or a black hole.

12m

Redshift

Light from a galaxy moving away arrives with a longer wavelength, shifted towards red.

12m

Evidence for the Big Bang: redshift and the CMBR

Galaxies are moving apart and microwaves fill all of space: both point to a hot, dense beginning.

11m

The Hubble constant and the age of the Universe

H₀ = v/d. Turn it over and 1/H₀ estimates how long the galaxies have been moving apart.

12m

10.

Stars and the Universe: practice

A timed drill of mixed questions: the Sun, light-years, life cycles, redshift and the Hubble constant.

11.

Stars and the Universe: exam practice

Exam-style questions with marks, mark schemes and full worked solutions.

15m

12.

Stars and the Universe: summary

The key points, the life-cycle map and the common mistakes on one screen, with cards to revise from.

About the creator

8bitlesson

Cambridge O Level, A Level and university courses, taught through interactive labs.

Mentora builds the sciences and mathematics as things you can move rather than videos you watch. Cambridge O Level and A Level mathematics, physics, chemistry and accounting, a primary mathematics track, and first-year university computer science. Every lesson works a real exam question end to end.