The human eye and the colourful world Worksheet-6

The human eye and the colourful world Worksheet-6

 

  1. What is the least distance of distinct vision ?

 

  1. What kind of lens is there in human eye ?

 

  1. Name the screen on which eye forms the image.

 

  1. Is cornea transparent to light ?

 

  1. What is the range of vision of a normal human eye ?

 

  1. Which phenomenon of vision is used in cinematography?

 

  1. What type of cells are lacking in a person who is colour blind ?

 

  1. Which type of retinal cells respond to brightness of light ?

 

  1. Which defect of vision can be rectified using a convex lens ?

 

  1. Which defect of vision can be rectified using a concave lens ?

 

  1. How is the vision of a person having cataract restored?

 

  1. Which defect of the eye can be corrected using a cylindrical lens ?

 

  1. Which colour has largest Wavelength ?

 

  1. Which colour suffers least deviation on passing through a prism ?

 

  1. What phenomenon causes twinkling of stars on a clear night ?'

 

  1. Which phenomenon is responsible for increasing the apparent length of the day by 4 minutes ?

 

  1. Why do stars appear higher than they actually are ?

 

  1. What enables the eye to focus objects at different distances?

 

  1. Why does it take some time to see objects in a cinema hall, when we just enter the hall ?

 

  1. How is the amount of light entering the eye controlled ?

 

Answer:

  1. least distance of distinct vision is 25 cm.

 

  1. double convex lens.

 

  1. Retina of the eye.

 

  1. Yes.

 

  1. From 25 cm to infinity.

 

  1. Property of persistence of vision.

 

  1. Cone shaped cells

 

  1. The rod shaped cells

 

  1. Hypermetropia or long sightedness.

 

  1. Myopia or short sightedness.

 

  1. By cataract surgery.

 

  1. Astigmatism.

 

  1. Red

 

  1. Red

 

  1. atmospheric refraction.

 

  1. Atmospheric refraction.

 

  1. Atmospheric refraction from upper rarer layers to lower denser layers.

 

  1. Change in focal length of eye lens by the action of ciliary muscles holding the eye lens.

 

  1. Pupil of the eyes take some time to expand and allow more light to enter the eye.

 

  1. The iris regulates the amount of light entering the eye by adjusting the size of the pupil of the eye.