Mock Test

Wave motion

by Anish
Updated On:

Wave motion

Total Questions: 44

11. Assertion (A): Radio waves bend in a magnetic field. [I.A.S. (PRE) 2008]

Reason (R): Radio waves are electromagnetic in nature.

Correct Answer: (d) (A) is false, but (R) is true.
Solution:Assertion (A) is false but reason (R) is correct because radio waves are electromagnetic in nature. So they are generally unaffected by magnetic and electric field.

12. cosmic rays - [56th to 57th B.P.S.C. (PRE) 2015]

Correct Answer: (a) are charged particles.
Solution:Cosmic rays are not the part of electromagnetic spectrum. They are immensely high-energy charged particles, travelling through space at a speed approaching that of light. They originated either from the sun or outside of our solar system.

13. Which of the following statement is not true about cosmic rays ? [U.P.P.C.S. (pre) 2005]

Correct Answer: (a) they are electromagnetic wave.
Solution:Cosmic rays are not the part of electromagnetic spectrum. They are immensely high-energy(very short wavelength) charged particles, travelling through space at a speed approaching that of light. They originated either from the sun or outside of our solar system.

14. Which of the following does not require a medium? [U.P.R.O/A.R.O.(MAINS) 2017]

Correct Answer: (a) Radiation
Solution:In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or through a medium. Electromagnetic radiations such as radio waves, microwaves, infrared, visible light, X-rays and gamma rays do not require a medium. On the other hand heat transmission by convection and conduction requires a medium

15. Which one of the following is associated with Albedo ? [U.P.P.C.S.(pre) 2019]

Correct Answer: (a) reflecting power.
Solution:Albedo is the fraction of light or radiation that is reflected by a body or surface. It is commonly used in astronomy to describe the reflective properties of planets, satellites, and asteroids. The range of albedo on the Earth's surface can be as high as 95% (0.95) for fresh snow cover and as little as 3% (0.03) for water.

16. The earth atmosphere is mainly heated by which one of the following ? [U.P.P.C.S.(pre) 2022]

Correct Answer: (b) longwave terrestrial radiation.
Solution:The energy released from the Sun is emitted as shortwave light and ultraviolet energy. When it reaches the Earth, some is reflected back to space (about 35%), some is absorbed by the atmosphere (about 14%), and some is absorbed in the Earth's surface (about 51%).

The insolation received by the Earth is in shortwave form and heats up its surface. The earth after being heated itself become a radiating body and the it radiate energy to the atmosphere in longwave form. This energy heats up the atmosphere from below .This process is known as terrestrial radiation.

The longwave terrestrial radiation is absorbed by the atmospheric gases particularly by carbon dioxide and the other greenhouse gases. Hence the earth atmosphere is mainly heated by the longwave terrestrial radiation.

17. The atmosphere is mainly heated by the : [68th B.P.S.C.(PRE) 2022]

Correct Answer: (a) long wave terrestrial radiation.
Solution:The energy released from the Sun is emitted as shortwave light and ultraviolet energy. When it reaches the Earth, some is reflected back to space (about 35%), some is absorbed by the atmosphere (about 14%), and some is absorbed in the Earth's surface (about 51%).

The insolation received by the Earth is in shortwave form and heats up its surface. The earth after being heated itself become a radiating body and the it radiate energy to the atmosphere in longwave form. this energy heats up the atmosphere from below .This process is known as terrestrial radiation.

The longwave terrestrial radiation is absorbed by the atmospheric gases particularly by carbon dioxide and the other greenhouse gases. Hence the earth atmosphere is mainly heated by the longwave terrestrial radiation.

18. Consider the following statements and choose the right options given below. [Chhattisgarh P.C.S.(PRE) 2023]

(1) Earth's surface re-emits heat in the form of Ultra- violet radiation.
(2) clouds and gases reflect about one forth of the incoming solar radiation.

Correct Answer: (b) Only the statement (2) is correct.
Solution:As per the NCERT, clouds and gases reflect about one-fourth of the incoming solar radiation, and absorb some of it but almost half of incoming solar radiation falls on Earth's surface heating it, while a small proportion is reflected back.

Earth's surface re-emits heat in the form of infrared radiation but part of this does not escape into space as atmospheric gases (e.g., carbon dioxide, methane, etc.) absorb a major fraction of it. Hence, only statement (2) is correct. However, as per some other sources clouds and gases reflect about 17-20 percent of the incoming solar radiation.

19. What is the distance between two successive crests or successive troughs called ? [45th B.P.S.C (pre) 2002]

Correct Answer: (b) wavelength
Solution:Wavelength means the distance measured in the direction of a wave form any given point to the next point in the same phase as from crest .The distance between two successive crests or two successive troughs is the wavelength of wave.

20. The velocity of electromagnetic waves is : [66th B.P.S.C (pre) 2020]

Correct Answer: (a) 3×10⁸ m/s
Solution:The velocity of the electromagnetic wave is the same and all travel at equal speed to the speed of the light in a vacuum hence the velocity of electromagnetic waves is about 3×108m/s

Anish

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