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प्रश्न
Give scientific reason:
One can sense colours only in bright light.
उत्तर
- The light sensitive screen of the eye, called the retina, has two types of light sensitive cells.
- Rod cells are concerned with vision in dim light and cone cells are responsible for the vision in presence of light.
- Cone cells are also concerned with colour perception. They do not respond to dim light or no light.
- Thus, the knowledge of the colour is possible in presence of light and not in dark.
- Hence, we can identify and differentiate colours in presence of light.
संबंधित प्रश्न
Distinguish between: aqueous humor and vitreous humor
Draw a neat and labelled diagram of the structure of the human eye.
What is the:
far point of a normal human eye?
What is the:
near point of a normal human eye?
What is the range of vision of a normal human eye?
Define the term "power of accommodation" of human eye.
Give the scientific names of the following parts of the eye:
carries signals from an eye to the brain.
Fill in the following blank with suitable word:
Most of the refraction of light rays entering the eye occurs at the outer surface of the.............
Fill in the following blank with suitable word:
The part of eye sensitive to light is...................
If you walk from a dark room into sunlight and back again into dark room, how would your pupils alter in size? What makes this happen?
The term " accommodation" as applied to the eye, refers to its ability to:
(a) control the light intensity falling on the retina
(b) erect the inverted image formed on the retina
(c) vary the focal length of the lens
(d) vary the distance between the lens and retina
How does the eye change in order to focus on near or distant objects?
(a) The lens moves in or out
(b) The retina moves in or out
(c) The lens becomes thicker or thinner
(d) The pupil gets larger or smaller
Which of the following changes occur when you walk out of bright sunshine into a poorly lit room?
(a) the pupil becomes larger
(b) the lens becomes thicker
(c) the ciliary muscle relaxes
(d) the pupil becomes smaller
The descriptions of five kinds of images are given below:
(a) diminished and virtual
(b) enlarged and real
(c) enlarged and erect
(d) real and inverted
(e) virtual and the same size
Which one of these describes the image formed:
(i) on the retina of the eye?
(ii) by a magnifying glass?
(iii) by a convex driving mirror on a car?
(iv) by a plane mirror?
(v) on the screen of a slide projector?
Which of the following have a wider field of view?
(a) Animals having two eyes on the opposite sides of their head.
(b) Animals having two eyes at the front of their head.
State whether the following statement is true or false:
Rabbit has eyes which look sideways.
What are the advantages of having two eyes instead of just one?
With both eyes open, a person's field of view is about:
(a) 90°
(b) 150°
(c) 180°
(d) 360°
Having two eyes gives a person:
(a) deeper field of view
(b) coloured field of view
(c) rear field of view
(d) wider field of view
With reference to the functioning of the eye, answer the question that follow:
Name the two structure in the eye responsible for bringing about the change in the shape of the lens.
State the main functions of the following:
Seminal Vesicles
Name the respective organs in which the following are located and mention the main function of each:
(i) Iris
(ii) Semicircular canals
Give the main function of the following:
Retina
Choose the correct answer.
Colour is detected by ____________
What is meant by power of accommodation of the eye?
What is a stereoscopic vision?
Differentiate between:
Retina and Choroid.
Name the following:
Yellow spot and ciliary muscles are found in.
Name the following:
The part of the eye responsible for change in the size of the pupil.
Choose the Odd One Out:
For the normal human eye, the near point is at ___________ cm.
Name the capacity of the eye lens to change its focal length as per need.
______ is the structural and functional unit of living organisms.
Why the human eye is compared with camera?
When light rays enter the eye, most of the refraction occurs at the ____________.
At noon the sun appears white as
Eyes of the nocturnal birds have large cornea and a large pupil. How does this structure help them?
The figure given below refers to the vertical section of the eye of a mammal. Study the figure carefully and answer the following questions.
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- Label the guidelines shown as 1 to 10.
- Write one important role of parts shown as 3 and 7.
- Write one structural difference between the parts shown as 9 and 10.
- Mention one functional difference between the parts shown as 6 and 8.
