Light (Physics) (Part-1)

 

Total Questions: 50

41. In the formation of a rainbow after a rain shower, sun light is_________ by tiny water droplets. [S.S.C. JE Electrical Exam 28.10.2020 (Shift-I)]

Correct Answer: (a) Dispersed
Solution:After the rain, small droplets of water remain in the clouds, which behave like a prism, from which the light is dispersed to form a band of colors called a rainbow.
  • Rainbows always form on the opposite side of the Sun. There is a red color on the top edge of the rainbow and a purple color on the bottom edge.

42. What is the name of the phenomena (driven by the scattering of light) in which mountain tops acquire a rosy or orange hue around sunrise and sunset? [S.S.C. Online Graduation Level (T-I) 4.03.2020 (Shift-III)]

Correct Answer: (d) Alpenglow
Solution:Alpenglow is an optical phenomenon in which mountain peaks scatter sunlight at sunrise or sunset by fine particles of ice that have accumulated on them.

Key Points about Alpenglow:

Cause: It occurs due to the scattering of sunlight by the atmosphere when the sun is just below the horizon. The sunlight is indirectly reflected or scattered by the atmosphere and clouds, illuminating the mountains with a soft reddish light.

Appearance: The glow typically has warm hues — pink, red, or orange — highlighting the peaks in a beautiful, diffuse light.

Difference from Direct Sunlight: Unlike direct sunlight, alpenglow happens without the sun being visible, giving mountains a magical glow during twilight hours.

13,100+ Alpenglow Stock Photos, Pictures & Royalty-Free Images - iStock | Mountain, Silhouette, Lake louise

43. Which of the following colours is NOT a primary colour? [S.S.C. JE Civil Exam 30.10.2020 (Shift-I)]

Correct Answer: (d) Orange
Solution:The colors which cannot be obtained by mixing two or more colors are called primary colors.

Orange is not the primary color but it is a secondary color among the colors given in the options.

Primary colors are

  1. Red,
  2. Yellow,
  3. and Blue (RYB).

Secondary colors are

  1. Green,
  2. Orange,
  3. and Violet (GOV).

44. Which glass is used to make spectacles? [S.S.C. Online CHSL (T-I) 22.01.2017 (Shift-I)]

Correct Answer: (a) Crook's glass
Solution:Crook's glass is made of cerium oxide and silica. It is used to make glasses.

45. What type of lens is used to correct vision of a person suffering from Myopia? [S.S.C. Online Graduation Level (T-I) 2.09.2016 (Shift-II)]

Correct Answer: (b) Concave lens
Solution:A person suffering from near-sightedness can see a near object clearly but cannot see clearly the object placed at a distance beyond a certain distance.

To correct this defect, a concave lens is used in the glasses of the person. Whereas a convex lens is used in a person's glasses to correct far-sightedness.

How do glasses correct nearsightedness? – Modern Vision Solutions

46. Which of the following is a human visual impairment, in which a person can see nearby objects clearly but cannot see distant objects clearly? [C.P.O. S.I. 7.06.2016 (Shift-I)]

Correct Answer: (a) nearsightedness
Solution:A person suffering from near-sightedness can see a near object clearly but cannot see clearly the object placed at a distance beyond a certain distance.

To correct this defect, a concave lens is used in the glasses of the person.
Whereas a convex lens is used in a person's glasses to correct far-sightedness.

How do glasses correct nearsightedness? – Modern Vision Solutions

47. Rajat has hypermetropia. What type of lens will the ophthalmologist recommend to correct his vision? [S.S.C. Online Graduation Level (T-I) 12.06.2019 (Shift-I)]

Correct Answer: (a) Convex
Solution:Hypermetropia, also known as farsightedness, is a common vision condition where a person can see distant objects clearly but has difficulty seeing nearby objects. This occurs because the eyeball is too short, or the cornea is too flat, causing light to focus behind the retina instead of directly on it.

A convex lens is thicker in the middle and thinner at the edges. Its primary function is to converge light rays. By placing a convex lens in front of the eye, it helps to bend the incoming light rays inward, effectively shifting the focal point forward onto the retina. This corrective action allows the eye to form a clear image of near objects.

Dioptis | Ametropias

48. Which of the following statements about hypermetropia is incorrect? [S.S.C. Online Constable GD 13.02.2019 (Shift-II)]

Correct Answer: (d) Growth in eye-ball is one of the causes of defect.
Solution:Hypermetropia (far-sightedness) is an eye defect in which a person can see distant objects clearly, but near objects are blurred.

The reason for the occurrence of farsightedness is the focal length of the eye lens-enlargement or shortening of the eyeball.

Hence statement (d) is wrong.

49. People who wear bifocal lenses have______ . [S.S.C. Online MTS (T-I) 14.10.2021 (Shift-II)]

Correct Answer: (d) presbyopia
Solution:Presbyopia is the gradual loss of your eye's ability to focus on nearby objects.
  • It's a natural, often annoying part of ageing.
  • Presbyopia usually becomes noticeable in your early to mid-40s and continues to worsen until around age 65.
  • Bifocal lenses are used to correct this defect.

50. Who invented the contact lens? [S.S.C. Online CHSL (T-I) 21.01.2017 (Shift-III)]

Correct Answer: (b) Adolf Gaston Eugen Fick
Solution:In 1888, Adolf Gaston Eugen Fick of Germany designed and used the first successful contact lens.