Ray Optics and Optical Instruments Class 12 MCQs Questions with Answers

1. Two thin lenses of focal lengths 20 cm and 25 cm are placed in contact. The effective power of the combination is:

2. A rod of length 10 cm lies along the principal axis of a concave mirror of focal length 10 cm in such a way that its end closer to the pole is 20 cm away from the mirror. The length of the image is

3. A convergent lens will become less convergent in :

4.  
Two concave mirrors have the same focal length but the aperture of one is larger than that of the other. Which mirror forms the sharper image and why?

5. Which produces additional luminiscence in a fluorescent tube?

6. Two beams of red and violet color are made to pass separately through a prism (angle of the prism is 60°). In the position of minimum deviation, the angle of refraction will be

7. When a beam of light is used to determine the position of an object, the maximum accuracy is achieved if the light is :

8. A double convex air bubble in water behaves as:

9.  
The air bubble inside water shine due to:

10. Which of the following colour of white light deviated most when passes through a prism?

11. Light year is the unit of:

12. An astronomical refractive telescope has an objective of focal length 20 m and an eyepiece of focal length 2 cm. Then

13. When light travels from one medium to another, which of the following does not change?

14.  
What is the relative refractive index of water with respect to glass?

15. Which of-the following is not a property of light?

16. A person is six feet tall. How tall must a plane mirror be if he is able to see his entire length?

17.  If a glass prism is dipped in water, its dispersive power

18.  
For a total internal reflection, which of the following is correct?

19. Radio waves from an antenna travel with the velocity of:

20.  
Which of the following cannot be polarised?