Define incident ray.

Label the different parts of the human eye and answer the question that follow.

Which part of the eye gives it its distinct colour?

Suggest some eye-care tips.

What will be the angle of reflection of a ray if the incident ray makes an angle of $90°$ to the reflected ray?

What will be the number of images formed if an object is placed between two parallel plane mirrors separated by $40 \mathrm{cm}$.