Question

What are the condition in which light will behave as a,wave particles or ray

Answer 1

Particle,ray and wave are properties/behavior/characteristics of light.


To put it simply, consider this: How would you define yourself ? Are you a good person or bad, are you caring or honest ? You could be honest one day but you could cheat some other day. These are your behavior. Some of your deeds can be accounted for one of your behavior and other deeds for other behavior.

Same goes with light. Phenomena like Reflection, Refraction and Interference are best explained with wave model of light. Photoelectric effect and Compton effect are best explained through particle model.

So, you must not try to decide between these two. Light has these characteristics embedded within it.

Now, the matter of concern is why or what causes light to behave differently in different cases.

In the double slit interference experiments with light and matter particles, we can see that only when the size of slits are comparable to wavelength of light/matter wave, they show typical wave phenomena. On a much larger scale, however, they show particle nature.

Hope this helps :)