Observe the following table 1) Find out from the table the medium having highest optical density and the medium with lowest optical density.

Question

Observe the following table and answer the following question.

Material medium	Refractive index	Material medium	Refractive index
Air	1.0003	Canada balsam	1.53
Ice	1.31	Rock salt	1.54
Water	1.33	Carbon Diasulphide	1.63
Kerosene	1.44	Dense flint glass	1.65
Fused quartz	1.46	Ruby	1.71
Turpentine oil	1.47	Sappire	1.77
Crown glass	1.52	Diamond	2.42
Benzene	1.50

1) Find out from the table the medium having highest optical density and the medium with lowest optical density. 

2) You are given kerosene, turpentine oil and water. In which of these does the light travel fast? Use the information given in the table. 

3) The refractive index of diamond is 2.42. What is the meaning of this statement? 

4) When light travels from water to crown glass, what happens? 

5) When light travels from diamond to air, what happens?

Answer 1

1) The medium with highest optical density is diamond as its refractive index is maximum, i.e. 2.42. The medium with lowest optical density is air, as its refractive index is minimum, i.e. 1.0003.

2) The refractive index of medium is given by the expression, n = c/v or v = c/n  This expression shows that light travels faster in the medium whose refractive index is minimum. From the table, we can find that water has the minimum value of refractive index. Therefore light travels faster in water.

3) This statement means that light travels 2.42 times faster in vacuum than in diamond. 

4) The light bends towards normal. 

5) The light bends away from the normal.