1On increasing the value of the angle of incidence (i) continuously, what could be the maximum value of the angle of refraction (r)?
2In which medium does the light go if the angle of incidence is increased after the angle of refraction has become 90°?
3A laser beam is sent through a bottle of water towards the stream of water flowing out of a hole. Does the light propagate along with the current of water?
4A laser beam is passed into a beaker of water through its side and the pointer is tilted to change the angle of incidence. Does the beam suffer total internal reflection from the surface of the water at a certain angle of incidence?
5A laser beam is directed normally at different faces of equilateral and isosceles right-angled glass prisms. In what condition does total internal reflection occur from a face of the prism?
6What is the critical angle? What are the critical angles of water and glass?
7What is total internal reflection of light? State its two conditions.
8Why is the word 'total' used in total internal reflection?
9Why can total internal reflection not take place when light goes from air into water?
10When a fish in an aquarium is viewed from a certain angle, it is seen below the water surface and also above it. Explain why.
11With the path of a ray, explain why total internal reflection takes place in an equilateral glass prism.
12Why are right-angled prisms used in periscopes, SLR cameras and binoculars?
13The critical angle of diamond is 24° and that of water is 49°. In which of the two is light trapped more easily? Why?