Main content
Course: Class 12 Physics (India) > Unit 10
Lesson 7: Diffraction due to single slit- Single slit interference
- More on single slit interference
- Worked Example: Diffraction slit width
- Diffraction: slit width & angular width
- Worked example: Size and Intensity of central maximum
- Diffraction: size and intensity of central maximum
- Why do soap bubbles appear colourful?
- How do telescopes see many stars where our eyes see only one?
© 2024 Khan AcademyTerms of usePrivacy PolicyCookie Notice
Why do soap bubbles appear colourful?
What do a soap bubble and a blue morpho butterfly have in common? Their wonderful vibrant colours? That's correct! Let's understand how thin film interference leads to such vibrant colours.
Created by Vibhor Pandey.
Want to join the conversation?
It really doesn't make sense to me why increasing the thickness of the film, which affects the path difference, would change the frequency/wavelength of the light wave.
Can someone explain?(2 votes)
When you consider the light wave equation, which is E=a cos(kx-wt), it becomes very clear. If the x changes, meaning that the path increases or decreases or there is a path difference, it is equivalent to adding a phase constant because the new path is x plus some value Δx *(x + Δx)*, which causes light to change phase, as the following example illustrates: E=a cos(k(x + Δx)-wt) ⇒ E=a cos(kx-wt+*Λxk*)(1 vote)