We know that light travels in a straight line in vaccum/air but is it possible to bend the path of light using external radiation or fields alone in air/vaccum.
Also why does refraction of light take place when it enters the boundary between materials of different refractive indices. I am told that its because velocities of light slows down/increases due to the change in the interaction with electrons with the two mediums, but what does that have to do with the actual bending of light ?