(a) A student is unable to see clearly the words written on the black board placed at a distance of approximately 3 m from him. Name the defect of vision the boy is suffering from. State the possible causes of this defect and explain the method of correcting it.
(a) A student is unable to see clearly the words written on the black board placed at a distance of approximately 3 m from him. Name the defect of vision the boy is suffering from. State the possible causes of this defect and explain the method of correcting it.
Text Solution
Verified by Experts
The boy is suffering from nearsightedness or Myopia in which a person cannot see the distant objects clearly though he can see the nearby objects clearly.
Myopia is caused -
due to lugh converging power of eye-lens (because of its short focal length), and
due to elongation of the eyeball.
This defect can be corrected by placing a concave lens in fron of the eye. Using concave lens of suitable focal length in the spectacles of such a person can correct this defect.
(b) The stars appear very-very small, so stars can be considered to be point sources of light as they are far away from the earth. The continuously changing atomosphere is able to cause variations in the light coming from a point-sized star due to atmospheric refraction because of which the star appears to be twinkling.
Myopia is caused -
due to lugh converging power of eye-lens (because of its short focal length), and
due to elongation of the eyeball.
This defect can be corrected by placing a concave lens in fron of the eye. Using concave lens of suitable focal length in the spectacles of such a person can correct this defect.
(b) The stars appear very-very small, so stars can be considered to be point sources of light as they are far away from the earth. The continuously changing atomosphere is able to cause variations in the light coming from a point-sized star due to atmospheric refraction because of which the star appears to be twinkling.
Topper's Solved these Questions
Similar Questions
Explore conceptually related problems
A 14 year old student is not able to see clearly the questions written of the black board placed at a distance of 5 m from him. Draw the diagram to show this defect?
A 14 year old student is not able to see clearly the questions written of the black board placed at a distance of 5 m from him. Name two possible cause of this defect.
A 14 year old student is not able to see clearly the questions written of the black board placed at a distance of 5 m from him. Name the type of lens used to correct this defect?
A 14 year old student is not able to see clearly the questions written of the black board placed at a distance of 5 m from him. Draw the diagram to show how this defect can be corrected.
Eye is a natural optical device by which human could see objects around him. It forms an inverted, real image on a light sensitive surface called retina. It works on the phenomenon of refraction of light through a natural convex lens. However, Sanjana was unable to see clearly the words written on the black board placed at a distance of approximately 3.5m from her. Her mother discussed the same with the doctor. Doctor explained her about this defect of vision and its correction. The human eye forms the image of the object at its ______
Eye is a natural optical device by which human could see objects around him. It forms an inverted, real image on a light sensitive surface called retina. It works on the phenomenon of refraction of light through a natural convex lens. However, Sanjana was unable to see clearly the words written on the black board placed at a distance of approximately 3.5m from her. Her mother discussed the same with the doctor. Doctor explained her about this defect of vision and its correction. Identify the possible cause of the defect from the following:
Eye is a natural optical device by which human could see objects around him. It forms an inverted, real image on a light sensitive surface called retina. It works on the phenomenon of refraction of light through a natural convex lens. However, Sanjana was unable to see clearly the words written on the black board placed at a distance of approximately 3.5m from her. Her mother discussed the same with the doctor. Doctor explained her about this defect of vision and its correction. What kind of defect Sanjana is suffering from?