A ray in oil (n = 1.52) reaches a boundary with water (n = 1.33) at 55.9 deg. Does it reflect internally or refract into the air?

Glass is transparent to visibile light under normal conditions; however, at extremely high intensities, glass will absorb most of the light incident upon it. this works through a process known as multiphoton absorption. in this process, several photons are absorbed at the same time. if very intense light whose photons carry 2ev of energy is shined onto a material with a band gap of 4ev, that light can be absorbed through two-photon absorption, because two photons have the right amount of energy to bridge the band gap. what is the minimum number of photons of 800-nm light that are needed to equal or exceed the band gap of fused silica glass

What is the increase in density of a medium due to wave travel?

Acoil suspended freely, points in some direction when no current is passed through it . can you tell what will happen when a current is passed though it?