9.3. Interference
Here we bring together all of the different ideas related to waves, interference and refraction to ook at a few specific examples. Firstly we look at diffraction gratings - which are commonly used to analyse light spectra. Finally we look at the phenomenon of thin film interference - the reason behind why bubbles and oil slicks have their characteristic rainbow sheen. There is some really interesting physics behind this, though it requires you to be confident using ideas about reflection, refraction and phase shift.
Before we start, take a look at this video by Crash Course
The section has been divded up as follows:
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Multiple Slits - we've looked at single and double, how about 3, 4 or 5 slits?
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Diffraction Gratings - used in astronomy to analyse light information from stars
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Thin Film Interference - why do oil slicks appear to have a rainbow colour?
Multiple Slit Interference
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Video Lessons
Chris Doner | Double Slit Recap | Multiple Slit Interference | IB Specific |
Resources
IB Physics | Topic 9 Notes | |||||
IB-Physics.net | Chapter 9 Summary | IB Revision Notes | ||||
Mr. G | 9.3 Teaching Notes | 9.3 Student Notes |
Questions
Cambridge University Press | Topic 9: Add Qs | Topic 9: Add Qs MS | Topic 9: MCQs | CUP Website Link | Freely available online | |
Grade Gorilla | 9.3 (Interference) MCQ | Topic 9 (Waves) End Quiz | Quick IB Specific Mixed MCQs | |||
Mr. G | 9.3 Formative Assessment | Topic 9 Summary Qs | IB Specific Questions | |||
Physics and Maths Tutor | Interference (AQA 2) | Interference MS (AQA 2) | A-Level Qs: overlapping content |
Diffraction Gratings
Video Lessons
Khan Academy | Diffraction Gratings | |||||
Physics Online | Diffraction Gratings | |||||
Science Shorts | Diffraction Gratings |
Resources
IB Physics | Topic 9 Notes | |||||
IB-Physics.net | Chapter 9 Summary | IB Revision Notes | ||||
Isaac Physics | Diffraction Gratings | Level 6 Beyond IB | ||||
Mr. G | 9.3 Teaching Notes | 9.3 Student Notes |
Questions
Cambridge University Press | Topic 9: Add Qs | Topic 9: Add Qs MS | Topic 9: MCQs | CUP Website Link | Freely available online | |
Dr French's Eclecticon | Interference, Doppler, Polarisation | Interference, Doppler, Polarisation Solutions | Link to Dr French's Site | Extension: Pre-University Material | ||
Grade Gorilla | 9.3 (Interference) MCQ | Topic 9 (Waves) End Quiz | Quick IB Specific Mixed MCQs | |||
Isaac Physics | Interference | |||||
Mr. G | 9.3 Formative Assessment | Topic 9 Summary Qs | IB Specific Questions | |||
Physics and Maths Tutor | Interference (AQA 2) | Interference MS (AQA 2) | A-Level Qs: overlapping content |
Thin Film Interference
Here we draw all these ideas we have looked at in our study of waves and wave behaviour to look at one specific example - why do bubbles or oil slicks appear to show rainbow patterns across their surface? This is all due to something called thin film interference, and it requires us to use our understanding of phase shift, reflection, wave interference, refraction and Snell's law to get our heads around it.
Video Lessons
Chris Doner | Thin Film Interference | IB Specific | ||||
Khan Academy | Thin Film Interference 1 | Thin Film Interference 2 |
Resources
IB Physics | Topic 9 Notes | |||||
IB-Physics.net | Chapter 9 Summary | IB Revision Notes | ||||
Mr. G | 9.3 Teaching Notes | 9.3 Student Notes |
Questions
Cambridge University Press | Topic 9: Add Qs | Topic 9: Add Qs MS | Topic 9: MCQs | CUP Website Link | Freely available online | |
Dr French's Eclecticon | Interference, Doppler, Polarisation | Interference, Doppler, Polarisation Solutions | Link to Dr French's Site | Extension: Pre-University Material | ||
Grade Gorilla | 9.3 (Interference) MCQ | Topic 9 (Waves) End Quiz | Quick IB Specific Mixed MCQs | |||
Mr. G | 9.3 Formative Assessment | Topic 9 Summary Qs | IB Specific Questions |
Additional Resources
IB Questions
A question by question breakdown of the IB papers by year is shown below to allow you to filter questions by topic. Hopefully you have access to many of these papers through your school system. If available, there may be some links to online sources of questions, though please be patient if the links are broken! (DrR: If you do find some broken links, please contact me through the site)
Questions on this topic (Section 9) are shown in royal blue.
Use this grid to practice past IB questions topic by topic. You can see from the colours how similar the question topic breakdown is year by year. The more you can familiarise yourself with the IB question style the better - eventually you will come to spot those tricks and types of questions that reappear each year.