Question

17. Read the following and answer any four questions from 17 (i) to 17 (v).
The absolute refractive index of a medium is simply called its refractive index. The ability of a medium
to refract light is also expressed in terms of its optical density. We have been using “rarer medium
and denser medium' which actually means optically rarer medium and optically denser medium. In
comparing two media the one with larger refractive index is optically denser and vice-versa.
Material medium
Canada Balsam
Refractive index
Material medium
Air
Ice
Refractive index
1.0003
1.53
1.31
Water
1.33
Rock salt
1.54
Alcohol
1.36
Kerosene
Fused quartz
Crown glass
1.44 Carbon disulphide
1.63
1.46 Dense flint glass
1.65
Turpentine oil
1.47 Ruby
1.71
Benzene
1.50 Sapphire
1.77
1.52 Diamond
2.42
(1) Name the medium having highest optical density in the following:
(a) Water
(6) Alcohol
(C) Air :
(d) Ice
(ü) Find the medium with lowest optical density in the following:
(a) Benzene
(b) Turpentine oil
(c) Rock salt
(d) Kerose
(iii) You are given kerosene, turpentine oil and water. In which of these does the light travel fastest?
(a) Kerosene
(6) Water
© Turpentine oil
(d) All of these
(iv) In which of the following mediums does the light travel slowest?
(6) Water
(c) Alcohol
(d) Benzene
(v) Which of the following statements is correct regarding the propagation of light of different colours
of white light in air?
(a) Red light moves fastest.
(1) Blue light moves faster than green light.
(c) All the colours of the white light move with the same speed.
(d) Yellow light moves with the mean speed as that of the red and the violet light.
(a) Air
©​

Answer 1

Answer:

blue light move faster than green light