Light: reflection and the eye · प्रकाश: परावर्तन और आँख
A free Physics lesson for Class 8 children.
When light hits a mirror it bounces back. This is reflection.
First law of reflection: the angle of incidence equals the angle of reflection.
Second law: the incident ray, the reflected ray and the normal at the point of incidence all lie in the same plane.
In a plane mirror the image is erect, virtual, the same size as the object, and as far behind the mirror as the object is in front. Left and right are swapped.
A smooth surface gives regular reflection. A rough surface scatters light in all directions: diffuse reflection.
In the eye, light enters through the cornea, the iris adjusts the pupil, the lens focuses the light, and the retina sends signals along the optic nerve to the brain.