Question

what do you mean bh tyndall effect

Answer 1

The Tyndall effect, also known as Willis-Tyndall scattering, is light scattering by particles in a colloid or else particles in a very fine suspension. It is named after the 19th-century physicist John Tyndall. It is similar to Rayleigh scattering, in that the intensity of the scattered light depends on the fourth power of the frequency, so blue light is scattered much more strongly than red light. An example in everyday life is the blue colour sometimes seen in the smoke emitted by motorcycles, in particular two-stroke machines where the burnt engine oil provides these particles.

Answer 2

Tyndall effect means scattering of light by the particles of colloids and the suspension solutions. a very common example of Tyndall effect is when the sun rays enter through a hole we can see small dust particles moving.  
hope it  helps :)