Question

All the objects reflect light falling on them,but brightness on different objects are different .justify

Answer 1

Visible light emitted or reflected from the objects around us,there exist coherent light and incoherent light.The laser is an example of coherent light,i.e it can be described by a wave with a known amplitude & phase.Amplitude is connected with the power that the beam distributes.In laser this is very concentrated.Amplitude is also connected with the number of photons in the beam. 

Answer 2

Answer:

We know that we have 2 types of reflection(regular and defused). Regular reflection happens on a smooth surface and defused reflection happens on a rough surface. There are many advantages of objects around us to cause diffused reflections on light and scatter the light falling on them in all directions. For example: If a book is lying on a table(The surface of the book is a rough surface) then it is because of the defused reflections that we can see it in all angles.  So basically the statement is right.