The yellow colour has a greater luminous efficiency as compared to the other colours. Can we increase the illuminating power of a white light source by putting a yellow plastic paper around this source ?

What is the effect on the interference fringes in a Young' double slit experiment due to each of the following operations. a. the screen is moved away from the plane of the slits. b. the (monolchromatic) source is replaced by another (monochromatic) source of shorter wavelength. c. the separation between the two slits is increased. d. the source slit is moved closer to the double slit plane: e. the width of the source slit is increased. f. The monochromatic source is replaced by a source of white light? (in each operation, take all parameters, other than the one specified, to remain unchanged).

An electron microscope uses electrons accelerated by a voltage of 50 kV. Determine the de Broglie wavelength associated with the electrons. If other factors ( such as numerical aperture, etc. ) are taken roughly to be the same, how does the resolving power of an electron microscope compare with that of an optical microscope which uses yellow light ( lambda_(y) = 5.9 xx 10^(-7) m ) .

The refractive index of a material changes by 0.014 as the colour of the light changes from red to violet. A rectangular slab of height 2.00 cm made of this material is placed on a newspaper. When viewed normally in yellow light, the letters appear 1.32 cm below the top surface of the slab. Calculate the dispersive power of the material.

The wavelength of light in the visible region is about 390 nm for violet colour, about 550 nm (average wavelength) for yellowgreen colour and about 760 nm for red colour. (a) What are the energies of photons in (eV) at the (i) violet end, (ii) average wavelength, yellow-green colour, and (iii) red end of the visible spectrum? ("Take h "= 6.63xx10^(-34)" J s and 1 eV" = 1.6xx10^(-19)J.) (b) From which of the photosensitive materials with work functions listed in Table 11.1 and using the results of (i), (ii) and (iii) of (a), can you build a photoelectric device that operates with visible light?

If we put a cardboard (say 20 cm xx 20 cm) between a light source and our eyes, we can't see the light. But when we put the same cardboard between a sound source and our ear, we hear the sound almost clearly, Explain.

In a Young's double slit experiment, two narrow vertical slits placed 0.800 mm apart are illuminated by the same source of yellow light of wavelength 589 nm. How far are the adjacent bright bands in the interference pattern observed on a screen 2.00 m away ?

A light source emits monochromatic light of wavelength 555 nm. The source consumes 100 W of electric power and emits 35 W of radiant flux. Calculate the overall luminous efficiency.