refraction of light

Question

Light travels from a region of heavy flint glass into a region of vacuum, making an angle of incidence of 50 degrees. Which of the following best describes the path of the light as it moves into the vacuum?

A) The light will bend toward the normal

B) The light will bend away from the normal

C)The light will continue without bending

D)The light will move in some manner not determined by the information here.

Answer 1

You can rule out C (because there's an angle of incidence and refraction happens) and D (because we do have the required information to answer this qualitatively). To answer this question, you only need to know which index of refraction, n, is larger (which you can look up in your book or over the internet). Once you know this all you have to do is to remember that:

1. If you are going from a medium with higher index to another with lower index (in this case, if n_glass > n_vacuum), then the outgoing ray bends away from the normal (B)
2. If you are going from a medium with a lower index to another with a higher index (in this case, if n_{glass <} n_vacuum ), then the outgoing ray bends towards the normal (A).

Which one do you think must be?