5.1.3

Photons

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Photon Model of Electromagnetic Radiation

We can think of electromagnetic radiation (light) as little packets of energy. We call these packets photons.

Frequency and energy

Frequency and energy

The energy of a photon is directly proportional to the frequency of the radiation.
- $E_{photon} = hf$
The letter 'h' is the Planck constant.
- It is a fundamental constant of nature and is equal to 6.63×10^-34 Js.

Energy of different photons

Energy of different photons

Gamma photons have the highest frequency and so carry the most energy.
Radio photons have the lowest frequency and so carry the least energy.

The Electron Volt

When dealing with energy levels of individual atoms, the SI unit of energy (the Joule, J) is far too big. So we need to define a more appropriate unit of energy, the electron volt, eV.

Definition of electron volt

Definition of electron volt

The electron volt is defined as the energy given to a fundamental charge, e, accelerated through a potential difference of 1 Volt.

Conversion

Conversion

To convert between J and eV, simply multiply or divide by the charge of the electron, e = 1.6×10^-19.
- 1 eV = 1.6 ×10^-19 J

Example - hydrogen

Example - hydrogen

Let's say the energy of an electron in a hydrogen atom is 13.6 eV.
To find this in Joules, use the equation shown previously:
- 13.6 eV = 13.6 × 1.6 ×10^-19 J
- 13.6 eV = 2.18 ×10^-18 J (3 s.f.)

1

Space, Time & Motion

1.1

Motion

1.1.1Motion Basics 1.1.2Graphs of Motion 1.1.3Uniform Acceleration Equations 1.1.4Projectile Motion 1.1.5Bouncing Ball Example

1.2

Forces

1.2.1Friction 1.2.2Terminal Speed 1.2.3Newton's Laws 1.2.4Exam-Style Question - Forces 1.2.5End of Topic Test - Newton's Third Law

1.3

Momentum & Impulse

1.3.1Momentum 1.3.2Momentum 2 1.3.3End of Topic Test - Newton's Laws & Momentum

1.4

Work, Energy & Power

1.4.1Work & Energy 1.4.2Conservation of Energy 1.4.3Power & Efficiency 1.4.4IB Multiple Choice- Work, Energy & Power

2

The Particulate Nature of Matter

2.1

Thermal Concepts

2.1.1Molecular Kinetic Theory Model 2.1.2Molecular Kinetic Theory Model 2 2.1.3Thermal Energy Transfer 2.1.4Thermal Energy Transfer Experiments 2.1.5Thermal Equilibrium 2.1.6Thermal Conductivity 2.1.7Heat Energy Transfer

2.2

Modelling a Gas

2.2.1Ideal Gases 2.2.2Ideal Gases 2 2.2.3End of Topic Test - Thermal Energy & Ideal Gases 2.2.4Exam-Style Question - Ideal Gases

3

Wave Behaviour

3.1

Oscillations

3.1.1Progressive Waves 3.1.2Simple Harmonic Motion

3.2

Travelling Waves

3.2.1Wave Speed & Phase Difference 3.2.2Longitudinal & Transverse Waves 3.2.3Electromagnetic Waves 3.2.4Electromagnetic Waves 2 3.2.5Sound Waves

3.3

Wave Characteristics

3.3.1Polarisation

3.4

Wave Behaviour

3.4.1Reflection & Absorption 3.4.2Reflection of Light 3.4.3Refraction 3.4.4Refractive index

3.5

Standing Waves

3.5.1Standing Waves 3.5.2Standing Waves 2 3.5.3End of Topic Test - Standing Waves 3.5.4IB Multiple Choice - Waves

3.6

Simple Harmonic Motion

3.6.1Simple Harmonic Motion 3.6.2Simple Harmonic Systems 3.6.3Energy in Simple Harmonic Motion 3.6.4End of Topic Test - Simple Harmonic Motion 3.6.5End of Topic Test - Simple Harmonic Motion

3.7

Single Slit Diffraction

3.7.1Diffraction

3.8

Interference

3.8.1Interference 3.8.2Interference 2 3.8.3Diffraction Gratings 3.8.4End of Topic Test - Diffraction

3.9

Doppler Effect

3.9.1Doppler Effect

4

Fields

4.1

Circular Motion

4.1.1Circular Motion 4.1.2Centripetal Force 4.1.3IB Multiple Choice - Circular Motion

4.2

Newton's Law of Gravitation

4.2.1Newton's Law 4.2.2Orbits of Planets & Satellites 4.2.3Escape Velocity & Synchronous Orbits 4.2.4End of Topic Test - Gravitational Fields

4.3

Fields

4.3.1Fields 4.3.2Gravitational Field Strength 4.3.3Gravitational Potential 4.3.4Electric Field Strength 4.3.5Electrostatic & Gravitational Forces 4.3.6Electric Potential 4.3.7IB Multiple Choice - Gravitational Fields

4.4

Fields at Work

4.4.1Radial Field Strength 4.4.2Orbits of Planets & Satellites 4.4.3Escape Velocity & Synchronous Orbits 4.4.4End of Topic Test - Gravitational Fields 4.4.5Uniform Electric Fields 4.4.6IB Multiple Choice - Electric Field & Potential

4.5

Electric Fields

4.5.1Electric Charge 4.5.2Conservation of Charge 4.5.3Coulomb's Law 4.5.4Current 4.5.5Potential Difference 4.5.6IB Multiple Choice - Electric Charge

4.6

Magnetic Effect of Electric Currents

4.6.1Magnetism 4.6.2Magnetic Field 4.6.3Magnetic Force 4.6.4Moving Charges in a Magnetic Field 4.6.5IB Multiple Choice - Magnetism

4.7

Heating Effect of Currents

4.7.1Circuits 4.7.2Resistance 4.7.3Power and Conservation 4.7.4IB Multiple Choice - DC Circuits

4.8

Electromagnetic Induction

4.8.1Electromagnetic Induction 4.8.2Electromagnetic Induction 2 4.8.3Magnetic Flux & Flux Linkage 4.8.4End of Topic Test - Electromagnetic Induction

4.9

Power Generation & Transmission

4.9.1Alternating Currents 4.9.2Operation of a Transformer

4.10

Capacitance

4.10.1Capacitance 4.10.2Parallel Plate Capacitor 4.10.3Energy Stored by a Capacitor 4.10.4Capacitor Discharge 4.10.5Capacitor Charge 4.10.6Magnetic Flux Density 4.10.7End of Topic Test - Capacitance & Flux Density

5

Nuclear & Quantum Physics

5.1

Discrete Energy & Radioactivity

5.1.1Atomic Spectra 5.1.2Atomic Structure 5.1.3Photons 5.1.4Discrete Energy Levels 5.1.5Alpha, Beta & Gamma Radiation 5.1.6Scientific Practices - Unstable Nuclei 5.1.7Radioactive Decay 5.1.8IB Multiple Choice - Atomic Physics

5.2

Nuclear Reactions

5.2.1Mass & Energy 5.2.2Nuclear Fission

5.3

The Interaction of Matter with Radiation

5.3.1Particles, Antiparticles & Photons 5.3.2Particle Interactions 5.3.3Classification of Particles 5.3.4Wave-Particle Duality 5.3.5Wave Functions & Probability 5.3.6IB Multiple Choice - Quantum Physics

5.4

Nuclear Physics

5.4.1Nuclear Instability & Radioactive Decay 5.4.2Nuclear Radius 5.4.3IB Multiple Choice - Nuclear Physics

6

Measurements

6.1

Measurements & Errors

6.1.1Fundamental Units 6.1.2SI Prefixes, Standard Form & Converting Units 6.1.3End of Topic Test - Units & Prefixes

6.2

Uncertainties & Errors

6.2.1Limitation of Physical Measurements 6.2.2Uncertainty 6.2.3Estimation 6.2.4End of Topic Test - Measurements & Errors

6.3

Vectors & Scalars

6.3.1Scalars & Vectors 6.3.2Vector Problems

Jump to other topics

1

Space, Time & Motion

1.1

Motion

1.1.1Motion Basics 1.1.2Graphs of Motion 1.1.3Uniform Acceleration Equations 1.1.4Projectile Motion 1.1.5Bouncing Ball Example

1.2

Forces

1.2.1Friction 1.2.2Terminal Speed 1.2.3Newton's Laws 1.2.4Exam-Style Question - Forces 1.2.5End of Topic Test - Newton's Third Law

1.3

Momentum & Impulse

1.3.1Momentum 1.3.2Momentum 2 1.3.3End of Topic Test - Newton's Laws & Momentum

1.4

Work, Energy & Power

1.4.1Work & Energy 1.4.2Conservation of Energy 1.4.3Power & Efficiency 1.4.4IB Multiple Choice- Work, Energy & Power

2

The Particulate Nature of Matter

2.1

Thermal Concepts

2.1.1Molecular Kinetic Theory Model 2.1.2Molecular Kinetic Theory Model 2 2.1.3Thermal Energy Transfer 2.1.4Thermal Energy Transfer Experiments 2.1.5Thermal Equilibrium 2.1.6Thermal Conductivity 2.1.7Heat Energy Transfer

2.2

Modelling a Gas

2.2.1Ideal Gases 2.2.2Ideal Gases 2 2.2.3End of Topic Test - Thermal Energy & Ideal Gases 2.2.4Exam-Style Question - Ideal Gases

3

Wave Behaviour

3.1

Oscillations

3.1.1Progressive Waves 3.1.2Simple Harmonic Motion

3.2

Travelling Waves

3.2.1Wave Speed & Phase Difference 3.2.2Longitudinal & Transverse Waves 3.2.3Electromagnetic Waves 3.2.4Electromagnetic Waves 2 3.2.5Sound Waves

3.3

Wave Characteristics

3.3.1Polarisation

3.4

Wave Behaviour

3.4.1Reflection & Absorption 3.4.2Reflection of Light 3.4.3Refraction 3.4.4Refractive index

3.5

Standing Waves

3.5.1Standing Waves 3.5.2Standing Waves 2 3.5.3End of Topic Test - Standing Waves 3.5.4IB Multiple Choice - Waves

3.6

Simple Harmonic Motion

3.6.1Simple Harmonic Motion 3.6.2Simple Harmonic Systems 3.6.3Energy in Simple Harmonic Motion 3.6.4End of Topic Test - Simple Harmonic Motion 3.6.5End of Topic Test - Simple Harmonic Motion

3.7

Single Slit Diffraction

3.7.1Diffraction

3.8

Interference

3.8.1Interference 3.8.2Interference 2 3.8.3Diffraction Gratings 3.8.4End of Topic Test - Diffraction

3.9

Doppler Effect

3.9.1Doppler Effect

4

Fields

4.1

Circular Motion

4.1.1Circular Motion 4.1.2Centripetal Force 4.1.3IB Multiple Choice - Circular Motion

4.2

Newton's Law of Gravitation

4.2.1Newton's Law 4.2.2Orbits of Planets & Satellites 4.2.3Escape Velocity & Synchronous Orbits 4.2.4End of Topic Test - Gravitational Fields

4.3

Fields

4.3.1Fields 4.3.2Gravitational Field Strength 4.3.3Gravitational Potential 4.3.4Electric Field Strength 4.3.5Electrostatic & Gravitational Forces 4.3.6Electric Potential 4.3.7IB Multiple Choice - Gravitational Fields

4.4

Fields at Work

4.4.1Radial Field Strength 4.4.2Orbits of Planets & Satellites 4.4.3Escape Velocity & Synchronous Orbits 4.4.4End of Topic Test - Gravitational Fields 4.4.5Uniform Electric Fields 4.4.6IB Multiple Choice - Electric Field & Potential

4.5

Electric Fields

4.5.1Electric Charge 4.5.2Conservation of Charge 4.5.3Coulomb's Law 4.5.4Current 4.5.5Potential Difference 4.5.6IB Multiple Choice - Electric Charge

4.6

Magnetic Effect of Electric Currents

4.6.1Magnetism 4.6.2Magnetic Field 4.6.3Magnetic Force 4.6.4Moving Charges in a Magnetic Field 4.6.5IB Multiple Choice - Magnetism

4.7

Heating Effect of Currents

4.7.1Circuits 4.7.2Resistance 4.7.3Power and Conservation 4.7.4IB Multiple Choice - DC Circuits

4.8

Electromagnetic Induction

4.8.1Electromagnetic Induction 4.8.2Electromagnetic Induction 2 4.8.3Magnetic Flux & Flux Linkage 4.8.4End of Topic Test - Electromagnetic Induction

4.9

Power Generation & Transmission

4.9.1Alternating Currents 4.9.2Operation of a Transformer

4.10

Capacitance

4.10.1Capacitance 4.10.2Parallel Plate Capacitor 4.10.3Energy Stored by a Capacitor 4.10.4Capacitor Discharge 4.10.5Capacitor Charge 4.10.6Magnetic Flux Density 4.10.7End of Topic Test - Capacitance & Flux Density

5

Nuclear & Quantum Physics

5.1

Discrete Energy & Radioactivity

5.1.1Atomic Spectra 5.1.2Atomic Structure 5.1.3Photons 5.1.4Discrete Energy Levels 5.1.5Alpha, Beta & Gamma Radiation 5.1.6Scientific Practices - Unstable Nuclei 5.1.7Radioactive Decay 5.1.8IB Multiple Choice - Atomic Physics

5.2

Nuclear Reactions

5.2.1Mass & Energy 5.2.2Nuclear Fission

5.3

The Interaction of Matter with Radiation

5.3.1Particles, Antiparticles & Photons 5.3.2Particle Interactions 5.3.3Classification of Particles 5.3.4Wave-Particle Duality 5.3.5Wave Functions & Probability 5.3.6IB Multiple Choice - Quantum Physics

5.4

Nuclear Physics

5.4.1Nuclear Instability & Radioactive Decay 5.4.2Nuclear Radius 5.4.3IB Multiple Choice - Nuclear Physics

6

Measurements

6.1

Measurements & Errors

6.1.1Fundamental Units 6.1.2SI Prefixes, Standard Form & Converting Units 6.1.3End of Topic Test - Units & Prefixes

6.2

Uncertainties & Errors

6.2.1Limitation of Physical Measurements 6.2.2Uncertainty 6.2.3Estimation 6.2.4End of Topic Test - Measurements & Errors

6.3

Vectors & Scalars

6.3.1Scalars & Vectors 6.3.2Vector Problems

Practice questions on Photons

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1
What is the symbol used for Planck's constant?Multiple choice
2
What is the definition of the electron volt?Flashcard
3
Units of energy:Fill in the list
4
What is 1.9 eV in Joules?Multiple choice
5
What is 25 eV in Joules?Multiple choice

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Atomic Structure

Discrete Energy Levels