What happens to the intensity of light from a bulb if the distance from the bulb is doubled? As a laser beam travels across the length of a room, its intensity essentially remains constant.
What geometrical characterstics of LASER beam is responsible for the constant intensity which is missing in the case of light from the bulb.

A LASER is a source of very intense, monochromatic, and unidirectional beam of light. These properties of a laser light can be exploited to measure long distances. The distance of the Moon from the Earth has been already determined very precisely using a laser as a source of light. A laser light beamed at the Moon takes 2.56 s to return after reflection at the Moon’s surface. How much is the radius of the lunar orbit around the Earth ?

Electromagnetic waves are those waves in which these are sinusoidal variation of electric and magnetic fields at right angle to each other as well as right angle ot the direction of propagation. The ratio of electric vector and magnetic vector gives the velocity of light and vecExxvecB gives the direction of propagation of electromagnetic wave. The electric field intensity produced by the radiations coming from 100 W bulb at a 3 m distance of E. The electric field intensity produced by the radiations coming from the 50 W bulb at the same distance is

A point source S emitting light of wavelength 600 nm is placed at a very small height h above a flat reflecting surface AB [Fig.6.07].The intensity of the reflected light is 36% of the incident intensity.Interfrerence fringes are observed on a screen placed parallel to the reflecting surface at a very large distance D from it. If the intensity t pint P corresponds to a maximum,calculate the minimum distance through which the reflecting surface AB sould be shifted so that the intensity at P again becomes maximum.

A beam of light of wavelength 600 nm from a distant source falls on a single slit 1.00 mm wide and the resulting diffraction pattern is observed on a screen 2m away. What is the distance between the first dark fringes on either side of the central fringe?

In a Young's double slit experiment,the slits are 1.5 mm apart.When the slits are illuminated by a monochromatic source and the screen is kept 1 m aprat from the slits,width of 10 fringes is measured as 3.93 mm.Calculate the wavelength of light used.What will be the width of 10 figes,when the distance between the slits and the screen is increased by 0.5 m?The source of light used remains the same.

An initially parallel cylindical beam travels in a medium of refractive index mu(I)=mu_0+mu_2I ,where mu_0 and mu_2 are positive constants and I is the intensity of the light beam.The intensity of the light beam is decreasing with increasing radius. The speed of the light in the medium is

A neutron beam of energy E scatters from atoms on a surface with a spacing d=0.1nm. The first maximum of intensity in the reflected beam occurs at theta=30 . What is the kinetic energy E of the beam in eV?

In a Young's double slit experiment,two slits are 1.5 mm apart and a screen in placed at a distance 1.2 m from the plane of the slits .The slits are illuminated with light of wavelength 6,000 overset @A .Find the inimum distance from the central maximum for which the intensity is half of the maximum intensity.

Light from an ordianry source(say a sodium lamp) is passed through a polaroid sheet P_1 .The transmitted light is then made to pass through a second polaroid sheet P_2 ,which can be rotated so that the angle (theta) betwen the two polaroid sheets varies from 0^@ to 90^@ .Show graphically the variation of he intensity of light transmitted by P_1 and P_2 as a function of the angle theta .Take the incident beam intensity as I_0 . Why does the light from a cleear blue portion of the sky,show a rise and fall on intesnity,when viewed through a polaroid ,which is rotated?