Question

What are the three laws of geometric optics?

Answer 1

The three laws of geometric optics:

1. Laws of reflection:
   
   The law of reflection defines that upon reflection from a smooth surface, the angle of the reflected ray is equal to the angle of the incident ray, with respect to the normal to the surface that is to a line perpendicular to the surface at the point of contact.
   The reflected ray is always in the plane defined by the incident ray and the normal to the surface at the point of contact of the incident ray.
2. Laws of refraction:
   
   The incident ray refracted ray, and the normal to the interface of two media at the point of incidence all lie on the same plane.
   The ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant. This is also known as Snell’s law of refraction.
   $\frac{\sin \mathrm{i}}{\sin \mathrm{r}}=\mathrm{constant}$
3. The law of rectilinear propagation:
   
   According to the law of rectilinear propagation of light we can say, Light travels in a straight line in a region of constant refractive index.