Hint:Light travels in a straight line in one material. This is called rectilinear propagation of light. But when light travels from one material(air, glass, water) to another,it bends and this bending of light is called refraction of light.
Complete answer: Let us understand the refraction in a bit detail, the reason behind the bending of light is the change in speed of light as it goes from one medium to another. Refractive index is a measure of how much light slows down when it goes into a new medium. It is denoted by the symbol ‘n’.
Refractive index of the vacuum is \[1\]. A refractive index of \[1.33\](water) means that the speed of light is \[1.33\] slower in water as compared to vacuum.Refractive mirror is the one which refracts or bends the incident ray into another medium.For example, when you look at a spoon in a glass of water, the submerged part of the spoon appears to be in a different place than expected.
Note:There are two possibilities when the refraction takes place, one is when light passes from a medium of lower $n$ such as air into a medium of higher $n$, such as glass, the light ray bends towards the normal( A imaginary line which is perpendicular or normal to the surface). Second possibility is when the light passes from a medium of higher $n$ to the medium of lower $n$, it bends away from the normal direction.