At angle of incidence equal to the critical angle, the angle of refraction is:

1. 0°
2. 30°
3. 90°
4. 180°

The condition required for total internal reflection to take place is:

1. light ray passes from a rarer to denser medium
2. light ray passes from a denser to rarer medium
3. angle of incidence is less than critical angle
4. none of the above

A total reflecting prism is:

1. right-angled prism
2. equilateral prism
3. right-angled isosceles prism
4. all of the above