Class 10 Science - Chapter The Human Eye and the Colourful World NCERT Solutions | Why do stars twinkle?
Why do stars twinkle?
Stars twinkling appears due to the atmospheric refraction of the starlight. When the starlight enters on the earth surface, refraction undergoes continuously with gradually changes in refractive index before it reaches the earth surface. The atmospheric physical condition changes, i.e, do not remain stationary, the apparent position (when star is slightly different from its original position) of the stars are also not stationary. When the refractive index changes continuously due to which path of the light rays from the stars keeps on changing the path continuously. As the path of rays of light that comes from the stars, goes on varying slightly. The apparent position of the stars fluctuates and the starlight enters the eye- sometimes the star may appear brighter, and sometime this effect is known as the twinkling effect.
More Questions From Class 10 Science - Chapter The Human Eye and the Colourful World
- Q:-
What is the far point and near point of the human eye with normal vision?
- Q:-
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.
- Q:-
Explain why the planets do not twinkle.
- Q:-
The human eye forms the image of an object at its
(a) cornea. (b) iris. (c) pupil. (d) retina.
- Q:-
What is meant by power of accommodation of the eye?
- Q:-
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?
- Q:-
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.
- Q:-
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?
- Q:-
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. - Q:-
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?
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