The far point of a healthy person is
The near point of the eye is the minimum distance of the object from the eye, which can be seen distinctly without strain. For a normal human eye, this distance is 25 cm.
The far point of the eye is the maximum distance to which the eye can see the objects clearly. The far point of the normal human eye is infinity.
A ray of light travelling in air fall obliquely on the surface of a calm pond. It will-
The light ray bends towards the normal as it travels from a rarer medium of air to a denser medium of water. Refraction is due to change in the speed of light as it enters from one transparent medium to another. The speed of light increases in rarer medium and decreases in denser medium.
The human eye forms the image of an object at its
The far point of a myopic person is 80cm in front of the eye. Which type of lens is required to correct the problem?
What Colour we obtain on mixing red green blue ?
We obtain white colour on mixing red green and blue.
The refractive indices of three media P, Q, R, are 1.73, 1.33 and 2.24 respectively. Arrange these media in increasing order of their optical density.
The inability among the elderly to see nearby objects clearly because of the weaking of the ciliary muscles is called-
Presbyopia is a condition associated with the aging of the eye that results in progressively worsening ability to focus clearly on close objects.
Light waves are
The muscles of the iris control the
It encircles the pupil of the iris and its function is to constrict the pupil in bright light via the pupillary light reflex or during accommodation.
At what rate the event should be projected to have the clear image ?
When shooting sports the frame rate needs to be much higher than 24. frames per second remember that to slow down footage. it's explosions or cellular division filming for science usually means shooting at a higher framerate more. frames researchers can better study their subject.
What is the least distance for clear vision in old age ?
The least distance up to which we can see the objects clearly without any strain is called least distance of distinct vision.In old age least distance is about 25cm.
The phenomena of light responsible for the working of the human eye is
The angle through which a ray of light turns on passing through a prism is called-
When do we say a person is colour blind ?
If an eye has near point at a distance of 0.5m, What is the power of lens required to correct it ?
For a hypermetropic eye u=-25cm and v=-50cm
substituting in the lens formula we get focal length is f=50cm =0.5m
from the formula P=1/f
so the power of the lens is 2 dioptre and the nature of lens is a converging lens or a convex lens.
The cause of Astigmatism is
The deviation in the path of ray of light can be produced-
In case of glass slab incident rays and the refracted rays are parallel to each other because medium of incidence and emergence happens to be the same. Hence the displacement of rays are lateral and emergent and incident rays are parallel to each other. In case of prism displacement is in the form of angular deviation.
When a light passes through a prism, it splits into its component colours. This phenomenon is called.
What is the observed colour of sky as seen from the moon surface ?
What is spectrum-
When a person is suffering from both myopia and hypermetropia, what type corrective lens are required-
Important defect of vision are-
If the person uses spectacles of power + 1.0 Dioptre, What is the nearest distance of distinct vision for him ?
∵ Near point = 75 cm and Power of lens = + 1 D
∴ P = 100 / f ( in cm )
f = 100 / P
= 100 / 1
= 100 cm
The distance of distinct vision v can be found as below.
Using lens formula here ,
1/f = 1/v - 1/u
⇒ 1/v = 1/f + 1/u
= 1 / 100 + 1 / - 75 = 3 - 4 / 300
= - 1 / 300
v = ₋300 cm
= - 3m ( in meters)
Ability of the eye lens to adjust its focal length is called
Power of accommodation is the ability of the eye lens to focus near and far objects clearly on the retina by adjusting its focal length.
The approximate focal length of the eye lens when the ciliary muscles are fully relaxed
The maximum focal length of eye lens is 2.5 cm.