Skip to main content

CRITICAL ANGLE FOR DIFFERENT COLOURS OF LIGHT

 CRITICAL ANGLE:

The critical angle is the angle of incidence in the denser medium for which the angle of refraction in the rarer medium is 90°.

FACTORS:

The critical angle of a medium depends on

1. The relative refractive index of the denser medium with respect to the rarer medium. Greater the refractive index, smaller the critical angle. 

For example: refractive index of glass is 1.5, critical angle is 42° and for diamond, refractive index is 2.4, the critical angle is 24°

2. The colour(wavelength) of the light. Longer the wavelength, greater  is the the value of the critical angle.

For example:  Red has longest wavelength among seven colours, so it has maximum value of the critical angle for a medium.


Comments

Post a Comment

Popular posts from this blog

UNIFORM CIRCULAR MOTION

In uniform circular motion,  1. Speed is constant. 2. Velocity is variable and acts along tangential direction  at a point. 3. Centripetal Force and acceleration act along the radius towards the centre if the circular path.  4. Centrifugal force appears to  act radially outwards. It is a virtual  ,fictitious force, not a real force.
Post a Comment
Read more

ECHO IN LIVING ROOM

Why is echo not heard in our living rooms? To hear echo, the minimum distance between the source and the reflector must be 17m. When this distance is more than 17m, the reflected sound can be distinguished from the original. As the length of our rooms is less than 17m, we don't hear echo.
Post a Comment
Read more