Human Eye

CLASS-VIII

THE HUMAN EYE

ASSIGNMENT-3

Q1. Name the outermost part of human eye.

Q2. Name the part of human eye which acts as a screen to obtain the image of an object.

Q3. Name two common defects of vision.

Q4. A child wears spectacles fitted with concave lenses. Name the defect of vision.

Q5. When we enter a dim-lit room from a bright light, we are not able to see the object in the room for some time. Explain, why?

Q6. Why do we have two eyes instead of one eye?

Q7. A child has difficulty in reading the black board while sitting in the last row. What could be the defect the child is suffering from? How can it be corrected?

Q8. What is the function of iris in the eye?

Q9. a) Which muscle controls the focal length of the eye lens?

       b) Which nerve sends the image to the brain?

Q10. Which phenomena is used in cinematography?

Q11. What happens to the image distance in the eye when we increase the distance of an object from the eye?

Q12. What type of lens is an eye lens?

Q13. Why does a person suffering from hypermetropia prefers to remove his spectacles while looking at distant objects? Explain.

Q14. Why do chickens wake up early and sleep early?

Q15. Visit an eye surgeon of your locality. Find out the following facts:

a)     Which part of our eye is donated at the time of eye donation?

b)    For how long the donated eye can be preserved?

c)     Who can’t donate his eyes?