Advertisements
Advertisements
Question
Why do diamonds sparkle?
Advertisements
Solution
Critical angle for diamond is quite less and is only 24°. Besides these diamonds are cut very sharp, making a large number of the refracting surfaces. Hence when a ray of light enters a diamond, it suffers a series of total internal reflections on account of a very small critical angle. This makes a ray of light literally trapped within the diamond for a little time and this trapped light energy makes a diamond sparkle.
RELATED QUESTIONS
Solve the previous problem if the paperweight is inverted at its place so that the spherical surface touches the paper.
(i) Define critical angle.
(ii) State one important factor which affects the critical angle of a given medium.
Plot a graph between
Angle of incidence versus angle of reflection,
(a) A ray of monochromatic light enters glass PQRS as shown in the fig. Complete the path of ray till it emerges from the glass. (Critical angle of glass is 420).
(b) Draw diagram of a prism periscope.
(c) What are the advantages of total internal reflecting prism over plane mirror?
How does a ray of light bend when it travels from denser to rarer medium.
A green light is incident from the water to the air-water interface at the critical angle (C). Select the correct statement.
For the same angle of incidence, the angle of refraction in four media A, B, C and D are 25°, 30°, 35° and 40° respectively. The speed of light is least in medium ______.
The entire light is reflected back into the denser medium is called ______.
What are the examples of total internal reflection in nature?
A rectangular block of glass ABCD has a refractive index 1.6. A pin is placed midway on the face AB (Figure). When observed from the face AD, the pin shall ______.
- appear to be near A.
- appear to be near D.
- appear to be at the centre of AD.
- not be seen at all.
