Ray Optics and Optical Instruments Class 12 Physics Chapter 9 MCQ Question Answer NCERT Solution

Class 12 Physics Chapter 9 objective type / mcq question answer of Ray Optics and Optical Instruments NCERT Solution in Hindi. NCERT Class 12 Physics MCQ Question Answer and Important Question Answer, Textual Question answer also Available for Various Board Students like HBSE, CBSE, UP board, Mp Board, RBSE and some other State Boards.

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NCERT Solution for Class 12 Physics Chapter 9 Ray Optics and Optical Instruments MCQ Question Answer.

Ray Optics and Optical Instruments Class 12 MCQ Question Answer


1. For total Internal Reflection light ray must go from where?
(A) Rarer to Denser medium
(B) Denser to Rarer medium
(C) Can go anywhere
(D) None of the above

Answer

Ans. (B) Denser to Rarer medium


2. Working of an optical fiber is based on which effect of light ?
(A) Reflection
(B) Total Internal Reflection
(C) Refraction
(D) Dispersion

Answer

Ans. (B) Total Internal Reflection


3. The bluish colour of sky is due to which effect of light ?
(A) Scattering
(B) Diffraction
(C) Refraction
(D) Dispersion

Answer

Ans. (A) Scattering


4. Phenomenon of splitting of light into its constituent colours is known as :
(A) Scattering
(B) Diffraction
(C) Refraction
(D) Dispersion

Answer

Ans. (D) Dispersion


5. Rainbow is a phenomenon due to :
(A) Reflection
(B) Refraction
(C) Dispersion
(D) All of these

Answer

Ans. (D) All of these


6. Mirage is a phenomena due to :
(A) Reflection
(B) Dispersion
(C) Scattering
(D) Total Internal Reflection

Answer

Ans. (D) Total Internal Reflection


7. Speed of Light in air is 3 × 810 m/s . For the water of refractive Index 4/3, the speed of light in water will be :
(A) 1.5 × 810 m/s
(B) 2 × 810 m/s
(C) 1 × 810 m/s
(D) 2.25 × 810 m/s

Answer

Ans. (D) 2.25 × 810 m/s


8. Which of the following is true regarding refractive index?
(A) It is the ratio of speed of light in vacuum to the speed of light in medium.
(B) Refractive index of water is 4/3
(C) Refractive index of air is 1
(D) All of the above

Answer

Ans. (D) All of the above


8. For which spectral colour of Light is the speed Maximum in glass ….
(A) Violet
(B) Indigo
(C) Blue
(D) Red

Answer

Ans. (D) Red


9. Unit of power of lens is
(A) 1m-1
(B) Dioptre
(C) Both (A) and (B)
(D) None of the above

Answer

Ans. (C) Both (A) and (B)


10. Larger aperture of objective lens in an astronomical telescope
(A) increases the resolving power of telescope.
(B) decreases the brightness of the image.
(C) increases the size of the image.
(D) decreases the length of the telescope.

Answer

Ans. (A) increases the resolving power of telescope.


11. For a glass prism, the angle of minimum deviation will be smallest for the light of
(A) red colour.
(B) blue colour.
(C) yellow colour.
(D) green colour

Answer

Ans. (A) red colour.


12. A biconvex lens of glass having refractive index 1·47 is immersed in a liquid. It becomes invisible and behaves as a plane glass plate. The refractive index of the liquid is
(A) equal to that of glass
(B) less than that of glass
(C) greater to that of glass
(D) None of the above

Answer

Ans. (A) equal to that of glass


13. The focal length of the objective of a compound microscope is
(A) greater than the focal length of eyepiece.
(B) lesser than the focal length of eyepiece.
(C) equal to the focal length of eyepiece.
(D) equal to the length of its tube.

Answer

Ans. (B) lesser than the focal length of eyepiece.


14. When a wave undergoes reflection at an interface from rarer to denser medium, adhoc change in its phase is :
(A) π/2
(B) 0
(C) π
(D) π/4

Answer

Ans. (C) π 


15. A biconcave lens of power P vertically splits into two identical plano concave parts. The power of each part will be
(A) 2P
(B) P/2
(C) √2P
(D) P/ 2

Answer

Ans. (B) P/2


16. The two Surfaces of a bi-convex Lens have equal radii of curvature R and its refractive Index n is 1.5. The focal Length of the Lens will be :
(A) R/2
(B) R
(C) –R
(D) 2R

Answer

Ans. (B) R


17. A thin convex lens of focal length 15 cm is placed in contact with a thin concave lens of focal length 15 cm. What is the power of the combination ?
(A) 0 D
(B) ∞ D
(C) 3 D
(D) 6 D

Answer

Ans. (A) 0 D


18. A thin convex lens of focal length 15 cm is placed in contact with a thin concave lens of focal length 10 cm. What is the focal length of the combination ?
(A) +25 cm
(B) +5 cm
(C) –30 cm
(D) –5 cm

Answer

Ans. (C) –30 cm


19. A thin convex lens of focal length 30 cm is placed in contact with a thin concave lens of focal length 20 cm. What is the focal length of the combination ?
(A) +50 cm
(B) –60 cm
(C) +10 cm
(D) –10 cm

Answer

Ans. (B) –60 cm


 

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