Skip to main content

ABSOLUTE REFRACTIVE INDEX AND RELATIVE REFRACTIVE INDEX

 ABSOLUTE  REFRACTIVE INDEX 


The absolute refractive index of a medium is the ratio of speed of light in vacuum and the speed of light in the medium.

Absolute refractive index = Speed of light in vacuum or air

                                                    Speed of light in the medium 

For example,

A.r.i of glass = speed of light in vacuum/speed of light in glass 

3×10⁸/2×10⁸= 3/2=1.5

Its value is equal or more than 1. For vacuum or air, its value is 1. So its minimum value is 1.


RELATIVE REFRACTIVE INDEX 


The relative refractive index of a medium (a) with respect to another medium (b) is the ratio of speed of light in medium (b) and the speed of light in medium (a).


Relative refractive index of  (a) wrt (b)=Speed of light in medium (b)

                                                                        Speed of light in medium (a)


For example, 

r.r.i of glass with water=speed of light in water/speed of light in glass 

=2.25×10⁸/2×10⁸=9/8=1.1

r.r.i of water wrt to glass= speed of light in glass/speed of light in water

=2×10⁸/2.25×10⁸= 8/9=0.88

Its value can be less than 1, more than 1 or equal to 1




Comments

Post a Comment

Popular posts from this blog

What is loudness of a sound?

Loudness of a sound is the characteristic of a sound which depend on the intensity of  energy it carries. Intensity of a sound is the amount of energy passing through a surface area of one square metre held perpendicular per sec. Intensity depends on square of amplitude of the wave passing. Hence we can say Loudness is directly proportional to the square of Amplitude. If amplitude is doubled, loudness becomes four times. Loudness depends on distance of source from the listener. Loudness depends on resonance also.
Post a Comment
Read more

Why is food cooked faster in pressure cooker?

Water boils at 100°C at normal pressure of 1 arm or 100000 Pascal. Boiling temperature increases  with the increase in pressure above the liquid surface. When we cook food in pressure cooker, the pressure increases due the retention of vapour and hence the boiling temperature increases in the pressure cooker upto 125°C As food is cooked at higher temperature than 100°C , it is cooked faster in the pressure cooker.
Post a Comment
Read more