Violet light refraction from air to glass

[batcave1985]

A ray of violet light enters a 60° glass prism at an angle of incidence of 40°. If the refractive
index of the prism material for violet light is 1.651

calculate:

(a) The angle of refraction for the air-glass boundary

(b) The critical angle for violet leaving the glass

(c) The velocity of the violet light in the prism

any help would be great.

at the moment I am on a)

i know that n=sin(i°)/sin(r°)

the wavelength of light is n=λair/λmedium( violet light)
= 1/1.651 = 0.6

sin(r)=sin(60)/0.6 = 1.4 but when i try to get the angle i get nothing.

 

[mfb]

n=sin(i°)/sin(r°)

n is larger than 1, so sin(r°) has to be smaller than sin(i°).
Why did you take the inverse of n in your calculation?