Does anybody has answers...??? Part-3

The Law of Refraction and Newton's first Law
The most simplest and elementary level of refraction is explained by through glass slab.The glass slab experiment of refraction is being taught in 8th or 9th class in Indian education system.I'm not here to discuss this topic mathematically, lets discuss it more theoretically, because I know maths(specially trigo. and calculus) can prove anything right and also wrong.So, no angle of incidence, angle of refraction,emergence, normal etc.... nothing....just purely LOGIC. I just thought and got clicked a very simple and base level violation of Physical law in it, Newton's first Law of Motion.It says, a body will remain in motion or in stationary until any external or internal force is acted upon it.


Like in my earlier posts I mentioned, I'm not here to prove anything or anyone logical and illogical, I'm just an another student of engineering not more than that. I just got clicked this in my mind. So, I would welcome any type of supportive theories and explanations.
  The law says--


--> A light ray bends towards the normal as it enters into the optically more dense medium.

--> A light ray bends away from the normal as it enters from optically more dense medium to less dense medium.

The Glass slab experiment shows that, a light ray experience a decrease in its velocity when it enters into the glass slab, i.e., from optically less medium to more dense medium, as the particle cloud inside the slab is more dense which resist the light ray to move at its entering speed.True.

              As the light ray leaves the glass slab surface it is recorded that the light ray has automatically gained its original speed,i.e., the speed at which the light ray has entered into the glass slab.How can this happen??? It is quite understandable that the particles force the light ray to decrease its velocity inside the glass slab.But, what about when it enters a less dense medium from more dense...?? How come the light ray has gained its original speed after leaving the surface of glass slab...??? and that too without any external force action upon it.....This what I feel is disturbing....Even if we neglect the Newton's first law....then what unknown force is being applied on the ray of light to regain its original speed...???
            If Newton's law doesn't have the correct explanation and answer for this, then what is the correct explanation?? Does the logic hidden in Properties of Light??? or elsewhere? I'm still in search of new explanations and theories which can give the correct explanation of this irregularity of light ray without any much mathematics involved....If anyone has...then I would really appreciate and welcome....