Why Does Refraction Occur at the Boundary Between Two Media?

Refraction occurs at the boundary of two media when light travels from one medium into the other and its speed changes but its frequency remains the same. ... This is because the light rays leaving the straw change direction when they hit the surface between the liquid and the air.

Why is there no refraction at the boundary of two media having equal refractive index?

When light travels from one medium to another, it generally bends, or refracts. ... Unlike reflection, refraction also depends on the media through which the light rays are travelling. This dependence is made explicit in Snell's Law via refractive indices, numbers which are constant for given media1.

Why does refraction occur?

Light refracts whenever it travels at an angle into a substance with a different refractive index (optical density). This change of direction is caused by a change in speed. ... When light travels from air into water, it slows down, causing it to change direction slightly. This change of direction is called refraction.