Optics Answers

The focal lengths of objective lens and eye lens of a Gallelian Telescope are respectively 30 cm and 3.0 cm. Telescope produces virtual, erect image of an object situated far away from it at least distance of distinct vision from the eye lens. In this condition, the Magnifying Power of the Gallelian Telescope should be :

For normal incidence of light from a medium of refractive index 1.42 onto a medium of refractive index 1.64, calculate the reflection and transmission co-efficients.

What condition(s) must be met to obtain sustained stimulated emission? Compare and contrast three level and four level pumping schemes for a laser.

What do you understand by temporal and spatial coherence of light? Is it true that observable interference fringe pattern cannot be obtained by using two incoherent sources in an interference experiment? Justify your answer.

For obtaining Newton’s rings due to reflected light, a convex lens is placed on a plane glass plate and irradiated by monochromatic light. Obtain an expression showing the relation between radii of successive dark rings related to each other?

A girl of height 150cm with her eye level at 140cm stands in front of a plane mirror of height 75cm fixed to a wall.The lower edge of the mirror is at a height of 85cm above her feet level.The height of her image the girl can see in the mirror is

Fraunhofer diffraction is a special case of Fresnel diffraction. Explain. Also discuss the concept of Fresnel half-period elements.

What kind of polarised light will you get if two plane polarised light waves of equal amplitude but having a phase difference of 90º are superposed? Justify your answer. Explain why unpolarised light reflected by a pile of plates is linearly polarized.

For obtaining Newton’s rings due to reflected light, a convex lens is placed on a plane glass plate and irradiated by monochromatic light. Obtain an expression showing the relation between radii of successive dark rings related to each other? If the space between the lens and plane glass plate in the Newton's ring set up is filled with a liquid of refractive index 1.38 and the wavelength of light used is 580 nm, calculate the diameter of the 4th dark ring. Take the radius of curvature of the lens to be 0.75 m.

Discuss the dependence of image forming ability of an optical device on the phenomenon of diffraction.