1. A concave mirror of focal length f produces an image n times the size of the object. If the image is real then the distance of the object is:

2. A convergent lens will become less convergent in :

3. A thin glass (RI = \(\frac{3}{2}\)) lens has optical power of - 5D in air. Its optical power in a liquid medium with RI = 1.6 will be:

4. On reflection from a denser medium, a light wave suffers a phase difference of:

5. The branch of optics dealing with the formation of images using the concept of straight line propagation of light is called:

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

7. Two lens of power -15 D and +5 D are placed in contact co-axially. The focal length of equivalent lens is:

8. Refractive index of water and glass are \(\frac{4}{3}\) and \(\frac{5}{3}\). A light ray is going to water from glass. Then, its critical angle will be:

9. The air bubble inside water shine due to:

10. When a ray of light (white) enters a lens, undergoes a change is: