monochromatic light and reflection

okgo

http://www.screencast.com/users/trin...1-237b20135d2c

I'm not sure why the answer is A. I tried reasoning myself that it has to do with the critical angle, but I can't seem to convince myself.

Stickey

Perhaps just a geometric problem?

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okgo

so perhaps the index of refraction does not matter?

Stickey

From that question, I wouldn't say so .. I assumed it continued to asking something else later on, more relevant to the refractive index?

okgo

lol no. This was a practice exam and half the people got it wrong. I guess the teacher was just being tricky.

Stickey

Very sneaky!

Well, from how it reads, I'd say that's the right answer

ehild

Think of phase change at both boundaries: air-alcohol and alcohol-plastic. What is the phase difference between the wave reflected from the alcohol-plastic interface and the directly reflected one (from the air-alcohol interface)?

ehild