Question

All objects reflects light falling on them, but brightness of 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. 

In this way all objects reflects loght falling on them but brightness pf different object differ.✌✌