Physics
What is a total reflecting prism? State three actions that it can produce. Draw a diagram to show one such action of the total reflecting prism.
Refraction Plane Surfaces
43 Likes
Answer
A prism having an angle of 90° between its two refracting surfaces and the other two angles each equal to 45° is called a total reflecting prism. In such a prism, the light incident normally on any of its faces suffers total internal reflection inside the prism.
Due to this property, a total reflecting prism is used for the following three purposes —
- To deviate a ray of light through 90°.
- To deviate a ray of light through 180°.
- To erect the inverted image without producing deviation in its path.
Below diagram shows the deviation of a ray of light through 90° by a total reflecting prism:
Answered By
34 Likes
Related Questions
A ray of light enters a glass slab ABDC as shown in figure and strikes at the centre O of the circular part AC of the slab. The critical angle of glass is 42°. Complete the path of the ray till it emerges out from the slab. Mark the angles in the diagram wherever necessary.
The refractive index of glass is 1.5. From a point P inside a glass slab, draw rays PA, PB and PC incident on the glass-air surface at an angle of incidence 30°, 42° and 60° respectively.
(a) In the diagram show the approximate direction of these rays as they emerge out of the slab.
(b) What is the angle of refraction for the ray PB?
(Take sin 42° = 2 / 3)
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.
A ray of light XY passes through a right-angled isosceles prism as shown in the adjacent diagram.
(a) What is the angle through which the incident ray deviates and emerges out of the prism?
(b) Name the instrument where this action of prism is put into use.
(c) Which prism surface will behave as a mirror?