Optics part (1)

Optics part (1)

Total Questions: 78

11. The speed of light in vacuum is nearly - [43rd B.P.S.C. (PRE) 1999]

Correct Answer: (b) 3×10⁸ m/sec
Solution:The speed of light in a vacuum is 3.00×108m/s . The speed of light in glass is 2.0×108m/s .

12. The speed of light is - [jharakhand P.C.S.(PRE) 2003]

Correct Answer: (c) 3×10⁸ m/sec
Solution:The speed of light in a vacuum is 3.00×108m/s. The speed of light in glass is 2.0×108m/s .

13. The speed of light in air depends on : [jharakhand P.C.S.(PRE) 2021]

Correct Answer: (d) optical density
Solution:The speed of light depends on the optical density of the medium in which it is travelling. The speed of light is inversely proportional to the optical density of a medium. When optical density is high, the speed of light is low. When optical density is low, the speed of light is high.

14. Velocity of light is maximum in - [U.P.P.C.S.(pre) 2021]

Correct Answer: (c) vacuum
Solution:The speed of light in a vacuum is maximum (c=3×108m/s).The speed of light decreases gradually in optically denser medium like water or glass.it is least in diamond.

15. Light travels at a maximum speed in : [Uttarakhand P.C.S.(PRE) 2021]

Correct Answer: (c) vacuum
Solution:The speed of light in a vacuum is maximum (c=3×108m/s).The speed of light decreases gradually in optically denser medium like water or glass.it is least in diamond.

16. The speed of light will be minimum while passing through- [I.A.S. (PRE) 1994, 67th B.P.S.C. (PRE)(RE.EXAM) 2022]

Correct Answer: (a) glass
Solution:Any of the object or material which has the highest refractive index has the minimum speed of light. The glass has the highest refractive index among the given options hence among the given options the speed of light will be minimum while passing through glass.

17. The time taken to reach the sunlight up to the surface of Earth is approximately- [42nd B.P.S.C. (Pre) 1997]

Correct Answer: (c) 8.5 minutes
Solution:The sunlight takes about 499 second or about 8.3 minutes to the reach earth.Thus the option (c) is the right answer.

18. Light from the sun to the earth reaches in : [U.P.P.C.S.(MAINS) 2006]

Correct Answer: (c) 8 minutes
Solution:The sunlight takes about 499 second or about 8.3 minutes to the reach earth.Thus the option (c) is the right answer.

19. The sunlight from the sun to the earth reaches in : [67th B.P.S.C. (PRE) 2019]

Correct Answer: (c) 8 minutes
Solution:The sunlight takes about 499 second or about 8.3 minutes to the reach earth.Thus the option (c) is the right answer.

20. Which of the following is highest velocity ? [U.P.P.C.S.(pre) 2018]

Correct Answer: (b) light
Solution:Nothing can travel faster than the light. The light waves can travel through a vacuum. The sound wave cannot travel through a vacuum the speed of light is maximum in a vacuum. The most galactic cosmic rays have energies between 100 mev ( corresponding to velocity for proton of 43 % of the the speed of light and 10 gev (corresponding to 99.6 % of the speed of light. The speed of highest energy cosmic rays could be extremely close to but still below the speed of light in a vacuum.

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