To get the best deal on Tutoring, call 1-855-666-7440 (Toll Free)
Top

The Human Eye and the Colourful World

The Eye

     Our eye is the most important natural optical instrument. The eye is nearly spherical in shape with a slight bulge in the front part.

Working of an Eye

     The light coming from an object enters the eye through cornea and pupil. The eye lens converges these light rays to form a real, inverted and diminished image on the retina.

Power of Accommodation

     The process by which the ciliary muscles change the focal length of an eye lens to focus distant or near objects clearly on the retina is called the accommodation of the eye.

Defects of Vision

     A normal eye can see all objects over a wide range of distances i.e., from 25 cm to infinity

Astigmatism

     Astigmatism is the most common vision problem resulting in distorted images, as light rays are prevented from meeting at a common focus.

Presbyopia

     Presbyopia is caused when the centre of the eye lens hardens making it unable to accommodate near vision. This condition generally affects almost everyone over the age of 50 - even those with myopia

Newton's Experiment - Dispersion of Light

     Sir Isaac Newton, while studying the images of heavenly bodies formed by a lens, found that the images were coloured at the edges.

Tracing the Path of Light Through a Prism

     Angle of deviation is the angle through which an incident ray deviates.Repeat this for different values of angle of incidence.

VIBGYOR

     Even though all colours of the visible spectrum travel with the same speed in vacuum, the speed of the colours of the visible spectrum varies when they pass through a transparent medium like glass and water.

Atmospheric Refraction

     Atmospheric refraction is the shift in apparent direction of a celestial object caused by the refraction of light rays as they pass through Earth’s atmosphere.

Summary

     The process by which the ciliary muscles change the focal length of an eye lens to focus distant or near objects clearly on the retina is called the accommodation of the eye.


Question and Answers

Question and Answers 1

Multiple Choice Questions

     



*AP and SAT are registered trademarks of the College Board.