Question

Why is the angel of reflection equal to angle of incidence when a light ray gets reflected from a surface

Answer 1

Hi friend here is your answer:

This is a good question. The law of reflection, and its corollary Snell’s law, are the basis of geometric, or ray optics. The laws of ray optics have such ubiquitious usage that it is easy to forget how mysteriousness their origins really are.

Ultimately the law of reflection requires some explanation based on the physics of how the light, i.e. the electromagnetic field behaves when it encounters a boundary between two different media. I’ve only seen this approached through the solution of Maxwell’s equations, usually for a plane wave incident on a boundary between two different media. By different, one means that the refractive index and absorption index change change discontinuously across the boundary. By the time one constructs a formal (and fairly laborious) mathematical solution to the propagation of an obliquely incident plane wave at an interface, properly ensuring that the various boundary conditions are met (continuity of magnetic induction normal to the surface, continuity of tangential electric field, normal component of electric displacement field discontinuous according to the surface charge density, and tangential magnetic induction discontinuous according to the surface current density) it drops out the math that the reflected wave vector has the same tangential amplitude as the incident wave vector and opposite perpendicular amplitude. If you haven’t taken the time to slog through a derivation like this, you might not find this explanation very satisfying. Or you might find it unsatisfying because my answer is unpersuasive or poorly written.

There are various other ways of demonstrating the law of reflection mathematically. Commonly people invoke Fermat’s principle, that the ray takes the path for which the transit time from source to observer is the shortest. This by itself is unsatisfying to me personally because it immediately raises the question of why or how Fermat’s principle applies and you get right back into the strange world of electromagnetism and Maxwell’s lovely equations. If that’s not enough, you can start considering the case of a moving mirror, where the weirdness of special relativity comes into play - and length contraction, doppler shifts and frames of reference must be considered. For this case the angle of incidence does not always equal the angle of reflection.

Also, if the incident medium is anisotropic, i.e. the speed of light varies with direction, then the law of reflection does not hold and the angle of incidence is not, in general, equal to the angle of reflection. This case does not apply in air or vacuum of course.

I hope it helps you .
please mark as brainliest.

@GOUTHAM CHOUDARY

Answer 2

As it's a plane mirror and in a plane mirror angle remains same.


This is the reason why we can look ourselves exactly same