Which of the following statement is correct according to the Laws of Refraction?
1
The angle of incidence is equal to the angle of refraction.
2
The ratio of the sine of the angle of incidence to the sine of the angle of refraction is a variable for the light of given colour and for the given pair of media.
3
The incident ray, the refracted ray, and the normal to the interface of the two transparent media at the point of incidence, all lie in planes perpendicular to each other.
4
The ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant for the light of a given colour and for the given pair of media.