1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Light Waves, Color, and Soap Bubbles

  1. Oct 31, 2011 #1
    1. The problem statement, all variables and given/known data

    A soap bubble is floating in the air. The wall of the bubble
    has an index of refraction of n = 1.33. It is observed that red and
    violet light are reflected from the surface of the bubble, but no
    green light is reflected. Compute the minimum thickness of the

    2. Relevant equations


    3. The attempt at a solution

    I'm pretty much just confused on where to start. I'm assuming it has something to do with the color destructively interfering with the soap bubbles, so that only some of the color reflects. Do I start by picking the smallest possible wavelength that includes both red and blue cones, and then assume that the speed of light is slower due to the soap material, THEN assume that the soap bubble has to be one wavelength long?
  2. jcsd
  3. Nov 1, 2011 #2


    User Avatar
    Homework Helper

    There is interference between the waves reflected from the front surface and the back surface of the wall of the bubble. The interference is destructive for green light.

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook