Light will always take the shortest time between two points, not the shortest distance $($this is known as Fermat's Principle$).$ Explain how these two things can be different, in the case of refraction.

b$.)$ Light passes from air into water. Fill in the following:

The light will $---$Select$---$ slow down speed up stay the same speed; light has a constant speed always. as it passes into the water.

The light will bend $---$Select$---$ towards away from none of the above the normal $($of the interface between the materials.$)$

c$.)$ Light passes from an n$=1\mathrm{.}5$ material into an n$=1\mathrm{.}3$ material. Fill in the following:

The light will $---$Select$---$ slow down speed up stay the same speed; light has a constant speed always. when it enters the second material.

The light will bend $---$Select$---$ towards away from none of the above the normal $($of the interface between the materials.$)$

If the n of the first material was instead $1\mathrm{.}7,$ then the amount by which the light was bent would be $---$Select$---$ less than before more than before the same as before $.$