The Human Eye and the Colourful World
Dispersion of Light Which light bends the most? credits:wpclipart |
Q1(NCERT): What is meant by power of accommodation of the eye?
Answer: Power of accommodation is the ability of the eye lens to focus near and far objects clearly on the retina by adjusting its focal length. Power of accommodation of the eye is limited. It implies the focal length of the eye lens cannot be reduced beyond certain minimum limit.
Q2(CBSE 2011): A person cannot see the objects distinctly, when placed at a distance less than 50 cm.
(a) Identify the defect of vision.
(b) Give two reasons for this defect.
(c) Calculate the power and nature of the lens he should be using to see clearly the object placed at a distance of 25 cm from his eyes.
(d) Draw the ray diagrams for the defective and the corrected eye.
Answer: (a) Defect of vision = Hypermetropia or Long-sightedness