Totally reflecting prisms
- Total internal reflection inside a 45o glass prism.
- The critical angle for the type of glass used to make the prism = 42o.
- The ray of light is turned through 90o.
- At A the ray of light is incident along the normal and passes straight through into the glass prism without being bent.
- At B the angle of incidence at the glass 鈥 air boundary is 45o which is greater than the The critical angle is the angle of incidence in the dense medium when the angle of refraction in the less dense medium is 90o.. Total internal reflection occurs, and the The angle between the reflected ray and the normal. is 45o.
- At C the ray of light is incident again along the normal and passes straight through into air without being bent.
- Total internal reflection inside a 90o glass prism.
- The critical angle for the type of glass used to make the prism = 42o.
- The ray of light is turned through 180o.