Light of wavelength 500nm in air enters a glass plate of refractive index 1.5. find its wavelength in glass.

50 Define focus of a convex lens. Draw a ray diagram showing the focus. 51 What is a simple microscope? 53 What is the consequence of making angle of incidence of light, at an interface, greater than the critical angle? 54 With the help of a labeled ray diagram show the formation of image of an object by a compound microscope.