When light wave travel from one transparent medium into another , the characteristics with undergo change are

When a ray of light travels from one transparent medium into another obliquely, the path of the light undergoes ____________.

When light goes from one medium to another, the characteristics that remain unaffected is its :

When a light ray travels from one medium to another with the same refractive index,

Ray of light bends as light travels from one medium to another.

Why does a ray of light bend when it travels from one medium into another ?