IB Physics Syllabus 2025

CONTENTS

1. IB Physics Syllabus: Course Overview

• Themes and Topics
• Teaching Order
• Teaching Hours

2. Comprehensive Learning Objectives for IB Physics

• Theme A: Space, Time and Motion
• Theme B: The Particulate Nature of Matter
• Theme C: Wave Behaviour
• Theme D: Fields
• Theme E: Nuclear and Quantum Physics

3. Practical Work

4. Frequently Asked Questions

5. TrIBe Physics (Direct Access to Me!)  👩🏻‍🏫

A.1 Kinematics

1. Define displacement, velocity and acceleration
2. Explain the difference between distance and displacement
3. Calculate instantaneous and average values of velocity, speed, and acceleration
4. Recognise situations where acceleration is uniform and non-uniform
5. Understand that the equations of motion are only valid for uniformly accelerated motion
6. Solve problems using the equations of motion
7. Define a projectile and resolve into vertical and horizontal components
8. Solve projectile motion problems for horizontal, oblique, and below horizontal projections (assuming negligible or absent air resistance, and close to the earth's surface with an acceleration of 'g')
9. Describe the effects of air resistance on the trajectory path, time of flight, velocity, acceleration, and terminal speed of a projectile.

A.2 Forces and Momentum

1. State Newton’s three laws of motion
2. Solve translational equilibrium problems using Newton’s 1st Law
3. Identify force pairs using Newton’s 3rd Law
4. Describe forces as interactions between bodies
5. Draw free-body diagrams and analyse them to find the resultant force on a system in one and two dimensions only
6. Understand the nature and use the following contact forces:
   normal, frictional, elastic, viscous drag, buoyancy
7. Understand the nature and use of the following field forces: gravitational, electric, magnetic
8. Define linear momentum and understand that it remains constant unless the system is acted upon by a resultant external force
9. Define Impulse as a resultant external force applied to a system and recall that impulse equals the change in momentum of the system
10. Derive Newton’s 2nd Law from the definition of net force as the rate of change of a momentum of an object, when mass is constant
11. Solve problems using momentum and impulse for collisions and explosion (one dimensional for SL and two dimensional for HL)
12. Understand the scenarios of elastic/inelastic collisions and explosions
13. State that bodies undergoing circular motion travel at a constant speed but still experience acceleration directed radially towards the centre of the circle
14. Draw a vector diagram to illustrate that the acceleration of a particle moving with constant speed in a circle is directed towards the centre of the circle.
15. Recognise the direction of velocity, acceleration and force vectors for an object in circular motion.
16. Understand and solve problems involving centripetal force, centripetal acceleration, period, frequency, angular displacement, linear speed and angular velocity.

A.3 Work, Energy and Power

1. State the principle of the conservation of energy

2. Recall that work done by a force is equal to the energy transferred in the system

3. Sketch and analyse energy transfers on Sankey diagrams

4. Determine work done (using W = Fscosθ) including cases where a resistive force acts and where force and distance are not parallel.

5. Recall and solve problems using fact that the mechanical energy of a system is the sum of kinetic energy, gravitational potential energy and elastic potential energy, in the absence of frictional forces.

6. Solve problems using the appropriate relationships for work done and energy transferred in systems where mechanical energy is conserved.

7. Define Power as the rate of work done, or rate of energy transfer.
   Solve problems involving power.

8. Define efficiency in terms of energy transfer or power. Solve problems involving efficiency.

9. Define and solve problems of the energy density of a fuel source

A.4 Rigid Body Mechanics (HL ONLY)

1. Describe the torque τ of a force about an axis

2. State that bodies in rotational equilibrium have a resultant torque of zero

3. State that an unbalanced torque applied to an extended, rigid body will cause angular acceleration

4. Describe the rotation of a body in terms of angular displacement, angular velocity and angular acceleration

5. Calculate the position 𝜽, angular displacement Δ𝜽, angular speed ⍵ and angular acceleration 𝛂 of an object using the equations of motion (SUVAT Equivalents) for uniform angular acceleration.
6. Define and perform calculations using the moment of inertia, I
7. Calculate using Newton’s second law for rotation as given by τ = Iα where τ is the average torque.
8. Calculate angular momentum, L for an extended body rotating with an angular speed
9. Understand that angular momentum remains constant (i.e. ∆L=0) unless the body is acted upon by a resultant torque
10. Explain how the action of a resultant torque will cause angular impulse
11. Calculate the kinetic energy of rotational motion

A.5 Galilean and Special Relativity (HL ONLY)

1. Define a reference frame and and understand the concept of an inertial reference frame

2. Explain that Newton's laws of motion are consistent in all internal reference frames, a concept known as Galilean relativity

3. Understand that in Galilean relativity, the position x' and time t' of an event are given by x'=x-vt and t'=t

4. Describe velocity addition for a Galilean transformation as given by
   u′ = u–v

5. Memorise the two postulates of special relativity

6. Calculate the motion of a particle at high speeds using the Lorentz transformation equations for the coordinates of an event in two inertial reference frames

7. Solve problems using the relativistic velocity addition equation

8. Calculate the invariant quantity of the space–time interval between two events

9. Define what is meant by proper time interval and proper length

10. Solve problems involving time dilation

11. Compute length dilation

12. Explain the concept of relativity of simultaneity

13. Interpret space–time diagrams to represent the motion of particles

14. Calculate the angle between the world line of a moving particle and the time axis on a space–time diagram

15. Interpret muon decay experiments to demonstrate evidence for time dilation and length contraction.

B.1 Thermal Energy Transfers

1. Explain the physical differences between the solid, liquid and gaseous phases in terms of molecular structure and particle motion (Note: be familiar with the terms melting, freezing, evaporating, boiling and condensing, and be able to describe each in terms of the changes in molecular potential and random kinetic energies of molecules

2. Define density using the equation 𝜌=m/V

3. Use Kelvin and Celsius temperature scales and convert between them (T/K = t/°C + 273)

4. Understand that the average kinetic energy of ideal gas molecules is directly proportional to the temperature (in kelvin) of the gas

5. Understand that internal energy is taken to be the total intermolecular potential energy and the total random kinetic energy of the molecules

6. Know that temperature difference depends on thermal energy transfer between bodies from hot to cold

7. Explain in terms of molecular behaviour why temperature does not change during a phase change

8. Define and solve problems with specific heat capacity and specific latent heat of fusion and vaporization

9. Describe on a molecular level how conduction, convection and radiation are mechanisms for thermal energy transfer

10. Perform calculations on the rate of kinetic energy transfer in conduction

11. Solve problems involving the Stefan-Boltzmann Law and Wien's displacement law

12. Define luminosity and apparent brightness AND solve problems involving luminosity, apparent brightness and distance

B.2 Greenhouse Effect

1. State the conservation of energy

2. Define and solve problems using emissivity and albedo

3. Know that the Earth's average albedo is 0.3; however, this varies daily depending on cloud formation and latitude

4. Define the Solar Constant, S, and explain why effective incident power on the Earth’s surface is S/4

5. Calculate equilibrium temperature of a body using energy balance between incoming and outgoing radiation intensity, including albedo, emissivity, and solar or other constants.

6. Know that the four greenhouse gases are CH4, H2O, CO2 and N2O, and that each gas is both man-made and naturally occurring in the atmosphere

7. Explain how the Earth radiates thermal radiation as a black body, which is absorbed by greenhouse gases, and then scattered in all directions (molecular energy levels), and subsequently heats up the Earth's surface

8. Define enhanced greenhouse effect as an augmentation of the naturally occurring greenhouse effect due to human activities

9. State that burning of fossil fuels is a primary cause of the enhanced greenhouse effect.

10. Explain how the main greenhouse gases cause enhanced greenhouse effect by referring to molecular energy levels, absorbed infrared radiation, resonance, and the subsequent emission of radiation in all directions

11. Calculate energy balance problems that include energy exchanged between the surface and the atmosphere of a body.

B.3 Gas Laws

1. State the assumptions of the kinetic theory of ideal gases, understanding this modelled system is used to approximate the behaviour of real gases

2. Understand that a real gas approximates to an ideal gas at conditions of low pressure, moderate temperature and low density

3. Define and solve problems using pressure as P=F/A

4. Define the amount of substance, n

5. Solve problems using the equation of state for an ideal gas and gas laws

6. Know that gas laws are limited to constant volume, constant temperature, constant pressure and the ideal gas law

7. Explain how the ideal gas laws is derived empirically from gas laws

8. Sketch and interpret changes of state of an ideal gas on pressure- volume diagrams

9. Calculate changes in pressure due to collisions with the walls of the container

10. Calculate internal energy, U of an ideal monatomic gas

B.4 Thermodynamics (HL Only)

1. Describe the first law of thermodynamics as a statement of conservation of energy and solve problems using the first law

2. Define the work done by or on a closed system

3. Calculate the change in internal energy for a system undergoing a change in temperature or volume

4. Describe the second law of thermodynamics in Celsius form, Kelvin form and as a consequence of entropy

5. Solve problems involving entropy changes

6. Understand isovolumetric, isobaric, isothermal and adiabatic processes
7. Solving problems for adiabatic processes for monatomic gases
8. Sketch and interpret cyclic processes which are used to run heat engines (Only graphical analysis will be required for determination of work done on a pV diagram when pressure is not constant)
9. Solve problems involving thermal efficiency
10. Define the Carnot cycle as a theoretical heat engine cycle that has the maximum possible efficiency of any heat engine and calculate the efficiency of a carnot cycle

B.5 Current and Circuits

1.  Define emf and electric potential difference, V

2. Describe how chemical cells and solar cells are energy sources in circuits

3. Be comfortable drawing circuit diagrams with a variety of components

4. Recognise current as the rate of flow of charge

5. Know that charge carriers within a metal are electrons, but they may be ions in other materials

6. Describe an ideal ammeter, an ideal voltmeter, and understand that most practical meters do not meet these requirements

7. Explain origin of electrical resistance and define resistance as R=V/I

8. State Ohm's Law

9. Know the I/V characteristics of ohmic conductors (metal wire at a constant temperature and non-ohmic conductors (filament lamp and diode)

10. Solve problems involving potential difference, current, charge, power, resistivity and resistance in both series and parallel circuits

11. Describe Internal Resistance in cells and solve problems using ε = I(R=r)
12. Describe how resistance varies in thermistors, light-dependent resistors (LDR) and potentiometers
13. Describe practical uses of potential dividers circuits

C.1 Simple Harmonic Motion

1. Explain the two conditions necessary for an object to oscillate with Simple Harmonic Motion

2. Recognise and use the defining equation for SHM, understanding the significance of the negative sign in a = -ω(^2)x

3. Define time period T, frequency f, angular frequency ⍵, amplitude A, equilibrium position and displacement in terms of a particle in SHM

4. Calculate time period , T for one complete oscillation for (1) a particle undergoing SHM, (2) a mass-spring system and (3) a simple pendulum

5. Describe the energy changes during one oscillation of an object undergoing SHM

6. Sketch and interpret graphs of examples of simple harmonic motion (including displacement-time, velocity-time, acceleration-time and acceleration-displacement graphs)

   
    

   Simple Harmonic Motion (HL Only)

7. Understand and explain how the phase angle φ is used to describe the state of a particle undergoing simple harmonic motion.
8. Calculate properties of an SHM oscillator
9. Describe the interchange of kinetic and potential energy during SHM, and solve problems using both graphical and algebraic methods

C.2 Wave Model

1. Explain the motion of particles for both transverse and longitudinal waves

2. Sketch and interpret displacement-distance graphs and displacement- time graphs for transverse and longitudinal waves

3. Define wavelength, frequency, time period, wave speed and amplitude

4. Be able to derive v=fλ and solve problems using this equation

5. Compare the nature of sound waves and electromagnetic waves

C.3 Wave Phenomena

1. Explain that waves travelling in two and three dimensions can be described through the concepts of wavefronts and rays

2. Define wave behaviour at boundaries in terms of reflection, refraction and transmission

3. Describe and sketch wave diffraction around a body and through an aperture

4. Sketch incident, reflected and transmitted wavefronts/rays between media (i.e. refraction)

5. Solve problems involving Snell's law, critical angle and total internal reflection

6. Be able to calculate the superposition of two waves / wave pulses

7. Describe the conditions necessary for double source interference

8. State the conditions necessary for constructive and destructive interference as given by path length difference

9. Understand the significance of Thomas Young's double slit experiment in the proof of light as a wave. Select and use s=λD/d for double slit experiments
    

   Wave Phenomena (HL ONLY)

10. Single Slit Diffraction at normal incidence through a rectangular slit:
    1. Describe the effect of changing the slit width
    2. Determine the position of the first interference medium
    3. Describe diffraction pattern produced from monochromatic light
11. Describe the interference pattern produced by a double slit on a screen, including the modulation by the single slit diffraction effect
12. Sketch and interpret intensity graphs of double slit interference patterns
13. Distinguish between the width of the slits and the separation of the slits in accounting for their effects on intensity graphs
14. Recognise that multiple slits and diffraction gratings can create interference patterns by considering path difference (for white light and a range of monochromatic light). Select and use nλ=dsinθ for diffraction grating problems

C.4 Standing Waves and Resonance

1.  Describe the conditions necessary for the formation of standing wave

2. Draw diagrams and identify nodes and antinodes, relative amplitude and phase difference of points along a standing wave

3. Describe the formation of standing waves in terms of superposition (standing wave patterns in strings and pipes). Boundary conditions for: Strings: two fixed boundaries, one fixed and one free boundary, and two free boundaries
   Pipes: two closed ends, one closed and one open end, and two open ends

4. Solve problems involving the frequency of a harmonic, length of the standing wave and the speed of the wave

5. Explain and give examples useful and destructive resonance including natural frequency and amplitude of oscillation based on driving frequency

6. Graphically describe the variation of the amplitude of vibration with driving frequency of an object close to its natural frequency of vibration

7. Describe the effects of light, critical and heavy damping on the system

C.5 Doppler Effect

1. Sketch and interpret the Doppler effect (for sound and electromagnetic waves) when there is relative motion between source and observer

2. Describe situations where the Doppler effect can be used (i.e. radars, red-shift of receding galaxies, moving objects emitting sound, ultrasounds reflected from blood cells, radars, etc.)

3. Recognise that electromagnetic waves (i.e. red-shift of galaxies) requires that the approximation equation should be used

4. Explain how shifts in spectral lines provide information about the motion of bodies like stars and galaxies in space.

    

   Doppler Effect (HL ONLY)

5. Solve problems involving the change in frequency or wavelength observed due to the Doppler effect to determine the velocity of the source/observer

D.1 Gravitational Fields

1. State Kepler's three laws of motion

2. Solve problems using Newton's Law of Gravitation between two spherical masses, where the masses are assumed to have uniform density and mass is concentrated at the centre

3. Recognise that when astronomical objects are in orbit, the gravitational force is equal to the centripetal force

4. Recall the definition for gravitational field strength

5. Determine the resultant gravitational field strength due to two bodies (restricted to points along the straight line adjoining the bodies)

6. Sketch the gravitational field lines for:
   i) radial field surrounding point or spherical masses and
   ii)uniform field close to the surface of massive celestial bodies and planetary bodies

    

   Gravitational Fields (HL ONLY)

7. Define gravitational potential energy and determine the potential energy of a point mass
8. Recognise gravitational potential, Vₚ, as a scalar and defined as the work per unit mass in bringing a small test mass from infinity to point P
9. Recognise the magnitude of the gravitational field as the rate of change of potential with distance
10. Draw equipotential lines on gravitational fields and explain that moving between equipotential lines requires work to be done on the point mass
11. Define escape speed and solve problems involving the speed required for an object to escape the gravitational field of a planet
12. Describe the qualitative effect of a small viscous drag force due to the atmosphere on the height and speed of an orbiting body.

D.2 Electric and Magnetic Fields

1. Know that there are positive and negative charges and predict the direction of forces between them

2. Solve problems using Coulomb's Law

3. State the law of conservation of electric charge

4. Describe Millikan’s experiment as evidence for quantisation of charge

5. Describe how electric charge can be transferred between bodies using friction, electrostatic induction and by contact, including the role of grounding (earthing)

6. Calculate the electric field strength of a uniform electric field

7. Sketch the electrostatic field lines for:
   i) radial field surrounding point or spherical charges,
   ii) inside and outside a spherical conducting body,
   iii) between two like or opposite charges and
   iv) uniform field lines between charged parallel plates (with edge effect)

8. Recognise that a higher field line density represents a larger electric field strength

9. Sketch magnetic field patterns around a bar magnet, a current-carrying wire, a current-carrying singular coil and an air core solenoid

10. Determine the direction of magnetic field around a long, straight current-carrying wire
     

    Electric and Magnetic Fields (HL ONLY)

11. Define electric potential energy and determine the potential energy for a system of two charged bodies
12. Recognise electric potential as a scalar and defined as the work per unit charge in bringing a small test charge from infinity to point P
13. Recognise the magnitude of the electric field strength as the rate of change of potential with distance
14. Draw equipotential surfaces and explain that moving between equipotential lines requires work to be done on the point charge

D.3 Motion in Electromagnetic Fields

1. Know that there are Describe the motion of a charged particle in
   (1) a uniform electric field
   (2) uniform magnetic field and
   (3) perpendicularly orientated uniform electric and magnetic fields

2. Calculate the magnitude and direction of the force on a charge moving in a magnetic field

3. State the magnetic force provides the centripetal force for a charged particle moving in a magnetic field

4. Calculate the charge-to-mass ratio for a charged particle by investigating its path in a uniform magnetic field.

5. Calculate the magnitude and direction of the force on a current- carrying conductor in a magnetic field

6. Calculate the magnitude and direction of the force per unit length between current-carrying parallel wires

D.4 Induction (HL Only)

1. Define Magnetic Flux

2. Recall and use Faraday's Law

3. Calculate the emf induced by a straight conductor moving perpendicularly to a uniform magnetic field

4. Explain Lenz's Law through conservation of energy

5. Explain how an emf is induced in the following situations: i) fixed coils in a changing magnetic field, and ii) ac generators

6. Explain the operation of a basic ac generator, including the effect of the generator frequency

E.1 Structure of the Atom

1. Describe Rutherford's scattering experiment, including the three main observations and conclusions of the structure of the atom

2. Understand that the absorption and emission spectra for each element is unique

3. Explain how spectral lines are evidence for the existence of discrete energy levels

4. Describe how emission and absorption spectra are produced

5. Calculate the frequency (or wavelength) of released or absorbed photons using the energy difference between energy levels in an atom

    

   Structure of the Atom (HL ONLY)

6. Calculate the radius of a nucleus and recognise that nuclear densities are approximately the same for all nuclei
7. Explain how the results of Rutherford's experiment change when higher energy alpha particles are used
8. Use energy conservation considerations to calculate the distance of closest approach in head-on scattering experiments to find the approximate value for the density of a nucleus
9. Describe the discrete energy levels in the Bohr model for the hydrogen atom and understand the terms of the quantisation of angular momentum

E.2 Quantum Physics (HL Only)

1. Describe a photon as a quanta of energy and momentum

2. Discuss the photoelectric effect and explain why the classical theory of light means a wave cannot be explained by the photoelectric effect. Define the work function and threshold frequency.

3. Solve problems about the photoelectric effect

4. Interpret the following graphs relating to the photoelectric effect:
   kinetic energy (y-axis) against frequency (x-axis)
   current (y-axis) against voltage (x-axis)
   stopping voltage (y-axis) against 1/λ (x-axis)

5. Recognise that matter can have wave-like properties (wave-particle duality)

6. Describe the experiment where electrons can be accelerated and diffracted through a thing graphite film, thus proving the wave nature of electrons

7. Calculate the de Broglie wavelength for particles

8. Explain how the Compton scattering of photons off electrons with increased wavelength is additional evidence of the particle nature of light

9. Calculate the shift in photon wavelength after scattering off an electron

E.3 Radioactive Decay

1. Define an isotope

2. Solve problems involving mass defect, binding energy and the atomic mass unit (memorise 1u = 931MeV) using

3. Define the mass-energy equivalence as given by E = mc^2 in nuclear reactions

4. Recall the definition for Binding Energy

5. Sketch and understand the general shape of the graph for average binding energy per nucleon against nucleon number

6. Calculate the frequency (or wavelength) of released or absorbed photons using the energy difference between energy levels in an atom

7. Define strong nuclear force

8. Describe the properties of alpha, beta and gamma radiation, including changes of state of nucleus, penetration, ionizing ability and real-life contexts

9. Complete decay equations for radioactive decay

10. Recognise that there are two types of beta decay (β− and β+) and explain the existence of neutrinos and anti-neutrinos

11. Define activity, count rate and half-life in radioactive decay

12. Determine the half-life of a radioactive nuclide using a decay curve or simple integral calculations, including the effect of background radiation

     

    Radioactive Decay (HL ONLY)

13. Describe evidence for the strong nuclear force
14. Understand the role of that ration of neutrons to protons for the stability of nuclides
15. State that the spectrum of alpha and gamma radiations provides evidence for discrete nuclear energy levels
16. State the continuous spectrum of beta decay as evidence for the neutrino
17. Define the decay constant
18. Explain that the decay constant approximates only in the limit of sufficiently small λt
19. Calculate the number of undecayed nuclei, activity and half-lives in radioactive decay for arbitrary time intervals

E.4 Fission

1. Describe how energy is released in spontaneous and neutron-induced fission

2. Calculate how much energy is released in a nuclear fission reaction

3. Describe the role of chain reactions in nuclear fission reactions

4. Explain the role of control rods, moderators, heat exchangers and shielding in a nuclear power plant

5. Describe the properties of the products of nuclear fission and their management, including the impact of long-term storage

E.5 Fusion and Stars

1. Describe the equilibrium between radiation pressure and gravitation in stars - how the star then achieves stellar equilibrium

2. Describe fusion as the source of energy in stars, the conditions required for fusion to occur and the basic fusion reactions present in stars on the main-sequence

3. Calculate the energy released in fusion reactions

4. Sketch and interpret HR diagrams, including the location of main sequence stars, red giants, super giants, white dwarfs, the instability strip and lines of constant radius

5. HR diagrams will be labelled with luminosity on the vertical axis and temperature

6. Convert between astronomical units (AU), light years (ly) and parsecs (pc)

7. Use stellar parallax as a method to determine the distance to celestial bodies

8. Explain how surface temperature may be obtained from a star’s spectrum, using intensity-wavelength graphs and/or Wien’s Displacement Law

9. Explain how the chemical composition of a star may be determined from the star’s spectrum, using the absorption spectrum of light received from the star

10. Calculate stellar radii using luminosity and surface temperature