A source of red light `(mu= 7000 overset(@)A)` produces intereference through two slit placed at a distanced .01cm. At what distance should a screen be placed so that interference band space 1 cm apart.

A convex lens of focal length 20 cm is placed at a distance of 30 cm from a screen. Where should an object be placed so as to form its real image on the screen?

An object of size 7.0cm is placed at 27cm in front of a concave mirror of focal length 18cm. At what distance from the mirror should a screen be placed,so that a sharp focussed image can be obtained? Find the size and the nature of the image.

What is interference of light? Write two essential conditions for sustained interference pattern to be produced on the screen. Why interference pattern is not detected when two coherent sources are far apart?

A beam of light consisting of two wavelengths 6500 A ˙ and 5200 A ˙ is used to obtain fringes in a Young's double slit experiment.Find the distance of the third bright fringe on the screen from central maximum for the wavelength 6500 A. The distance between the slits is 2mm and the distance between the plane of the slits and the screen is 120 cm

When an object is placed at a distance of 60 cm from a convex mirror, the magnification produced is 1/2. Where should the object be placed to obtain a magnification of 1/3?

In double slit experiment using light of wave length 320 nm the angular width of a fringe formed on a distant screen is 0.1^@ . What is the spacing between the two slits?