AQA A-Level Physics Paper 1: Discussion

Any questions of final queries for tomorrows exam?

http://filestore.aqa.org.uk/sample-papers-and-mark-schemes/2017/june/AQA-74081-QP-JUN17.PDF

do you mind explaining 3.3

are there any derivations we need to know

are there any derivations we need to know

Ok, so the first thing to consider is that the higher the refractive index of a material, the more light will refract (bend) in it.

Due to that reason, you can think of this question as two separate sections almost. What happens to red light - it's going to be refracted as it's critical angle is going to be higher, due to the lower refractive index

And blue light is going to be Totally Internally Reflected as its critical angle is lower than that of green light and therefore is critical and is going to be smaller.

i thought refractive index is the speed of light in a substance so why would it be different for blue and red light

Probably due to the speed of light in the substance of each wavelength of light being different. That's why when you pass white light through a prism a rainbow appears. And in-fact exactly why rainbows exist.