Question

What is regular and irregular reflection.... What is difference between then????

Answer 1

In regular reflection incident light rays and reflected light rays all are parallel

In irregular reflection incident light rays are parallel but reflected light rays are not parallel they get scattered

OR


Regular reflection
1) After reflection rays are parallel. 
2) It obeys law of reflection 
3) Surface used for reflection is smooth. 
Irregular Reflection 
1) After the reflection rays are not parallel. 
2) It does not obey law of reflection. 
3) Surface used for reflection is rough.

Answer 2

Regular reflection occurs
when a beam of light falls on a smooth and polished surface .

Irregular reflection takes place when the reflecting surface is not smooth or polished .
example:- wood, paper ,wall etc