What does cylindrically symmetric charge distribution mean? Use Gauss’s law to determine the electric field of an infinite solid cylinder of radius R having volume charge density p at a point outside it.
See Answer →Two positively charged particles each having charge 20 C, are kept at a distance of 2.0 m from each other. Determine the force on each charge and the electric field due to each charge. Show the force and electric field vectors on appropriate diagrams. What is the resultant force at a point midway from the two charges along the straight line joining them?
The refractive indices of the core and cladding materials of an optical fibre are 1.64 and 1.53 respectively. Calculate the numerical aperture and light gathering capacity of the fibre.
See Answer →Two energy levels of an atomic system are separated by energy corresponding to frequency 5.0 Hz. Assume that all atoms are in one or the other of these two energy levels. Compute the fraction of atoms in the upper energy level at temperature 600 K. Take kg = 1.38
JK
and h = 6.6
Js.
Why pumping is necessary for laser action? Compare and contrast three level and four level pumping schemes for lasers.
See Answer →An atomic system consisting of two energy levels with population of higher energy level less than that of the lower level, is in thermal equilibrium. Show that the absorption of radiation dominates stimulated emission if radiation of appropriate frequency is introduced into the system. Comment on the consequences of this fact for laser action
See Answer →A beam of parallel light of wavelength 6000 Å is incident normally on a 1 rupee coin of diameter 3 cm. If an observation screen is placed at a distance of 1 m from the coin, how many Fresnel zones would be obstructed by it (the coin)? For what separation between the coin and the screen, only 5 zones would be cut off
See Answer →6 principal maxima are observed in the diffraction pattern due to a diffraction grating. Calculate the number of lines per cm in the grating if the wavelength of the light is 5000 Å
See Answer →A grating has 10,000 lines per cm. What is the maximum number of principal maxima that can be formed for light of wavelength 5
cm?
Derive an expression for the intensity of the diffraction pattern obtained due to Fraunhofer diffraction from a single slit.
See Answer →With the help of a diagram, explain the working of Michelson interferometer. Explain how Michelson interferometer can be used for determining the refractive index of a thin plate
See Answer →Interference fringes are produced by a beam of monochromatic light incident normally on a wedge shaped film of refractive index 1.5. The angle of the wedge is 15 seconds of an arc and the two successive dark fringes are 0.4 cm apart. Calculate the wavelength of light.
See Answer →A wedge shaped film is obtained by placing a thin wire between two plane glass plates at one end keeping them in contact with each other at the other end. When the film is illuminated by light of wavelength 6000 Å, 40 fringes are observed. Calculate the radius of the wire
See Answer →The wavelength of light used in Young’s double slit experiment is 6000 Å. The second and the fourth bright fringes from the centre of the fringe pattern are located respectively at 10.24 mm and 12.40 mm. If the observation screen is placed at a distance of 1 m from the slits, calculate the separation between the slits.
See Answer →For a crystal, the refractive index no for the o-ray is 1.5442 for light of wavelength 6 . The least thickness of the crystal used as a quarter wave plate is found to be 1.65
m. Determine the refractive index ne for the e-ray in this crystal.
Two plane polarised light waves are propagating along the positive z-direction such that their electric field vectors are mutually perpendicular. These waves are superposed. Obtain the condition under which the resultant wave will be circularly polarised
See Answer →A beam of light is propagating in vacuum and its frequency is constant. Show that the average energy carried by it per unit area is proportional to the associated electric field vector.
See Answer →State and explain Fermat’s principle. Using this principle, derive Snell’s law of refraction
See Answer →Design a half adder using only NAND gates.
See Answer →Design and draw a Mod-9 counter.
See Answer →