1. In geometrical optics, the refractive index of a medium is defined as
2. A convex mirror always forms an image that is
5. Optical fibers work on the principle of
1 out of 4
6. The unit of refractive index is
7. Interference is evidence of the
8. Destructive interference occurs when path difference is
9. In interference, bright fringes correspond to
10. Newton’s rings are produced due to
2 out of 4
11. The phase difference for destructive interference is
12. Fresnel diffraction occurs when
13. Diffraction confirms the
14. Rayleigh criterion is associated with
15. The grating equation is
3 out of 4 
