Advertisements
Advertisements
प्रश्न
When do we consider a student sitting in the class to be myopic? List two causes of this defect. Explain using a ray diagram how this defect of eye can be corrected.
Advertisements
उत्तर
Myopia means near sightedness, when a student is unable to use clearly far away objects we consider the student to have myopia.
Causes :
Excessive curvature of the eye lens
Alongation of the eyeball
APPEARS IN
संबंधित प्रश्न
In a Std. X class out of 40 students 10 students use spectacles, 2 students have positive power and 8 students have negative power of lenses in their spectacles.
Answer the following questions:
(1) What does the negative power indicate?
(2) What does the positive power indicate?
(3) Generally which type of spectacles do most of the students use?
(4) What defect of eyesight do most of the students suffer from?
(5) Give two possible reasons for the above defect.
A person with a myopic eye cannot see objects beyond 1.2 m distinctly. What should be the type of the corrective lens used to restore proper vision?
An eye has a far point of 2 m. What type of lens in spectacles would be needed to increase the far point to infinity? Also calculate the power of lens required. Is this eye long-sighted or short-sighted?
A young man has to hold a book at arm's length to be able to read it clearly. The defect of vision is:
(a) astigmatism
(b) myopia
(c) presbyopia
(d) hypermetropia
A person can read a book clearly only if he holds it at an arm's length from him. Name the defect of vision:
if the person is a young man
Which part of the eye is grafted in a needy patient from a donated eye?
Give Reason:
Why do we see clearly in the central region of the retina?
Differentiate between:
Myopia and Hypermetropia.
Give Technical Term:
The type of lens used to correct myopia is
A person cannot see distinctly objects kept beyond 2 m. This defect can be corrected by using a lens of power:
