A total reflecting right angled isosceles prism can be used to deviate a ray of light through :
(a) 30∘ (b) 60∘ (c) 75∘ (d) 90∘
(d) 90∘
A total reflecting equilateral prism can be used to deviate a ray of light through:
Show with the help of a diagram how a total reflecting prism can be used to turn a ray of light through 90∘. Name one instrument in which such a prism is used.