State any two difference between interference of light and diffraction of light.

Laser light of wavelength 630 nm is incident on a pair of slits which are separated by 1.8 mm. If the screen is kept 80 cm away from the two slits, calculate:

i) fringe separation i.e., fringe width

ii) distance of 10^th bright fringe from the centre of the interference pattern.

Show graphically the intensity distribution in Fraunhofer's single diffraction experiment. Label the axis.

A point object O is placed at a distance of 15 cm from a convex lens L of focal length 10 cm as shown in figure below. On the other side of the lens, a convex mirror M is placed such that its distance from the lens is equal to the focal length of the lens. The final image formed by this combination is observed to coincide with the object O. Find the focal length of the convex mirror.

What is chromatic aberration? How can it be minimised or eliminated?

Draw a labelled ray diagram of an image formed by compound microscope, when the final image lies at the least distance of distinct vision (D).

With regard to an astronomical telescope of refracting type, state how you will increase it's:

i) magnifying power
ii) resolving power

38.

In an experiment of photoelectric effect, the graph of maximum kinetic energy E_k of the emitted photoelectrons versus the frequency  of the incident light is a straight line AB as shown in the figure below.


Find:

i) Threshold frequency of the metal

ii) Work function of the metal

iii) Stopping potential for the photoelectrons emitted by the light of frequency  Hz

i) State how de- Broglie wavelength ( of moving particles varies with their linear momentum (p).

ii) State any one phenomenon in which the moving particles exhibit wave nature.

On the basis of Bohr's theory, derive an expression for the radius of the n^th orbit of an electron of hydrogen atom.