Objective

Question-2. What is the shortest distance to the near point for a normal eye?

Ans- 25 cm

Question-3. What is that distant (distant) point as far as the eye can see clearly, what is it called?

Ans- Far point

Question-4. What is the far-point distance for a normal eye?

Ans- at infinity

Question-5. Who controls the size of the pupil?

Ans- iris (iris)

Question-7. Where is the image of an object formed?

Ans- on the retina

Question-8. The focus-distance of the eye-lens is (automatically) adjusted. What is this property of the eye-lens called?

Ans- Adjustment capacity

Question-9. What is the reduction in the ability of the retina to form a clear image called?

Ans- Visual impairments

Question-10. What are the types of vision defects?

Ans- 3 [nearsightedness, farsightedness and shortsightedness]

Question-11. Apart from these three vision defects, there is another vision defect, which is called.

Ans- Abstinence

Question-12. Which defect of vision is called when the eye cannot see distant objects clearly?

Ans- Myopia

Question-13. What are the causes of nearsightedness?

Ans-

→ Enlargement of the eyeball

→ Decrease in the focal length of the eye lens

Question-14. Which lens is used to correct myopia?

Ans- Concave lens

Question-15. What is the defect of vision when the eye cannot see nearby objects clearly?

Ans- Farsightedness

Question-16. What are the causes of farsightedness?

Ans-

→ Shortening of the eyeball

→ Increase in the focal length of the eye lens

Question-17. Which lens is used to correct farsightedness?

Ans- Convex lens

Question-18. Due to the hardening of the eye lens, its adjustment ability decreases, then what is it called?

Ans- A little foresight

Question-19. Which lenses are used for the treatment of farsightedness?

Ans- Bifocal lens (bifocal lens)

Question-20. Which lenses are used to treat amblyopia?

Ans- Cylindrical lens

Question-21. Why do stars twinkle?

Ans- Due to atmospheric refraction

Question-22. White light is made up of a mixture of how many colors?

Ans- 7

Question-23. Which color of glass has the highest refractive index?

Ans- violet

Question-24. What is the phenomenon of splitting of white light into its constituent colors called?

Ans- Dispersion of light

Question-25. Who divides white light into its constituent colours?

Ans- Prism

Question-26. What is the group of constituents of white light called?

Ans- spectrum

Question-27. Which color has the least deviation in a prism?

Ans- Red coloured

Question-28. Which color diverges the most in a prism?

Ans- Violet

Question-29. What is the distance covered by a wave in one period called?

Ans- Wavelength

Question-30. What are Lights?

Ans- an electromagnetic wave

Question-31. Which color of light has the longest and shortest wavelength?

Ans- Red color is most and purple color is least.

Question-33. What is it called when light is scattered in different directions after falling on a microscopic particle?

Ans- scattering of light

Question-34. The sky is visible due to the scattering of sunlight?

Ans- Blue

Question-35. There is no atmosphere in space due to which—

Ans- There is no scattering of light.

Question-36. Astronauts see the sky—

Ans- Black

Question-37. What is the scattering of light by colloidal particles called?

Ans- tyndall effect

Question-38. Which part of the eye receives most of the refraction of the light rays entering the eye?

Ans- on the outer surface of the cornea

Question-39. The focus-distance of the eye lens is changed by?

Ans- by ciliary muscles

Question-40. When the ciliary muscles of the eye are relaxed, the eye lens—

Ans- gets thinner

Question-41. When the ciliary muscles of the eye are relaxed, the focal length of the eye lens—

Ans- increases

Question-42. What is the condition called when the crystalline lens of the eye becomes milky and cloudy?

Ans- cataracts

Question-43. focal length of the eye lens in myopia—

Ans- decreases

Question-44. The focal length of the eye lens in hyperopia—

Ans- increases

Question-45. Which natural phenomenon of light is the formation of rainbow in the sky?

Ans- deflection

Question-46. What is the reason for the blood appearing of the sun at sunrise and sunset?

Ans- red dispersion

Question-47. The horizontal field of vision of a human eye is approx.

Ans- 150⁰

Question-48. Human eyes have the maximum field of vision.

Ans- 180⁰

Question-49. Which point of the human eye is most sensitive to light?

Ans- yellow point/spot

Question-50. How many pages are there in a glass prism?

Ans- 5

Question-51. What is the angle between the two side faces of a prism called?

Ans- prism angle

Question-52. What is the angle formed between the incident ray and the emergent ray of a prism called?

Ans- deviation angle

Question-53. When light of high intensity falls on the eye, the size of the pupil becomes.

Ans- small

Question-54. When low intensity light falls on the eye, the pupil becomes sized.

Ans- big

Question-55. Which lens is in the upper part of the bifocal lens used in shortsightedness?

Ans- concave lens

Question-56. Where is the image of an object formed in the eye of a person with nearsightedness?

Ans- in front of the retina

Question-57. Where is the image of an object formed in the eye of a person with farsightedness?

Ans- behind the retina

Question-58. A student sitting in the last row has difficulty in reading the blackboard, what defect of vision is this student suffering from?

Ans- myopia

Question-59. Which type of lens works in a simple microscope?

Ans- convex lens

Question-60. What is used to get spectrum?

Ans- Prism

Question-61. Which color of the spectrum has the highest inclination?

Ans- red

Question-62. What type of lens is found in the human eye?

Ans- convex lens

Question-63. What is the shortest distance for clear vision?

Ans- 25 cm

Question-64. When sunlight passes through the atmosphere, which color light is scattered more strongly by the tiny particles of air?

Ans- Blue

Question-65. Which color of light has the highest refractive index?

Ans- red

Question-66. Which of the following is not a sensory organ?

(a) ear (b) eye (c) nose (d) brain

Ans- (d) brain

Question-67. What is the scattering of light from particles suspended in a colloidal solution called?

Ans- tyndall effect

Question-68. What is the value of one Angstrom?

Ans- 10‾¹⁰ meters

Question-69. The slide is first viewed with a compound microscope.

Ans- at 10x

Question-70. Which phenomenon of light represents the Tyndall effect?

Ans- light scattering