Name the defect of vision in person
a. Whose near point is more than 25cm away?.
b. Whose far point is less than infinity.
Uploaded bysunil View Answer
What is a spectrum?
Can visible light be scattered by atoms/molecules in earth’s atmosphere?
Why does clear sky look blue?
What is the basic cause of atmospheric refraction?
Why does the sky appear black instead of blue to an astronaut?
What is meant by scattering of light ?
What phenomenon causes twinkling of star on a clear night ?
Which defect of vision can be rectified using a concave lens ?
Which color has largest wavelength ?
As light rays pass from air into glass prism, are they refracted towards or away
from the normal ?
Why do different colours deviate through different angles on passing through
a prism?
What is range of vision ?
What is the function of optic nerve in human eye ?
Who was the first person to obtain the spectrum of sunlight ?
What type of lens is used for correcting hypermetropia ?
What is the nature of image formed on the retina of the eye ?
State one effect produced by the scattering of light by the atmosphere ?
Name one defect of vision which cannot be corrected by any type of spectacle
lenses ?
Name the muscle responsible for bringing change in the focal length of the eye
lens ?
What is the least distance of distinct vision of a normal human eye ?
Why does the sky appear dark instead of blue to an astronaut?
Uploaded bysandeep View Answer
Why does the Sun appear reddish early in the morning?
Explain why the planets do not twinkle?
Why do stars twinkle?
What happens to the image distance in the eye when we increase the distance of an object from the eye?
Why is a normal eye not able to see clearly the objects placed closer than 25 cm?
Make a diagram to show how hypermetropia is corrected. The near point of a hypermetropic eye is 1 m. What is the power of the lens required to correct this defect? Assume that the near point of the normal eye is 25 cm.
The far point of a myopic person is 80 cm in front of the eye. What is the nature and power of the lens required to correct the problem?
A person needs a lens of power -5.5 dioptres for correcting his distant vision. For correcting his near vision he needs a lens of power +1.5 dioptre. What is the focal length of the lens required for correcting (i) distant vision, and (ii) near vision?
The change in focal length of an eye lens is caused by the action of the
(a) pupil
(b) retina
(c) ciliary muscles
(d) iris
The least distance of distinct vision for a young adult with normal vision is about
(a) 25 m
(b) 2.5 cm
(c) 25 cm
(d) 2.5 m
The human eye forms the image of an object at its
(a) cornea (b) iris (c) pupil (d) retina
The human eye can focus objects at different distances by adjusting the focal length of the eye lens. This is due to
(a) presbyopia
(b) accommodation
(c) near-sightedness
(d) far-sightedness
A student has difficulty reading the blackboard while sitting in the last row. What could be the defect the child is suffering from? How can it be corrected?
What is the far point and near point of the human eye with normal vision?
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?
What is meant by power of accommodation of the eye?