51.

Yellow light is used in single slit diffraction experiment with slit width 0.6 mm. If yellow light is replaced by X-rays, then the pattern will reveal that

• no diffraction pattern

• that the central maxima narrower

• less number of fringes

• more number of fringes

In an interference experiment, third bright fringe is obtained at a point on the screen with a light of 700 nm. What should be the wavelength of the light source in order to obtain 5th bright fringe at the same point ?

• 630 nm

• 500 nm

• 420 nm

• 750 nm

The phenomenon of rotation of plane polarised light is called

• Kerr effect

• double refraction

• optical activity

• dichroism

As a result of interference of two coherent sources of light energy is

• redistributed and the distribution does not vary with time

• increased

• redistributed and that distribution changes with time

• decreased

A beam of light of wavelength 600 nm from a source falls on a single slit 1 mm wide and the resulting diffraction pattern is observed on a screen 2 m away. The distance between the first dark fringes on either side of thecentral bright fringe is

• 2.4 cm

• 2.4 mm

• 1.2 mm

• 1.2 cm

In a Young's double slit experiment, the separation between the two slits is 0.9 mm and the fringes are observed one metre away. If it produces the second dark fringe at a distance of 1 mm from the central fringe, the wavelength of the monochromatic source of light used is

• 450 nm

• 400 nm

• 500 nm

• 600 nm

When light is incident on a diffraction grating, the zero order principal maximum will be

• spectrum of the colours

• white

• one of the component colours

• absent

H-polaroid is prepared by

• orienting herapathite crystal in the same direction in nitrocellulose

• using thin tourmaline crystals

• stretching polyvinyl alcohol and then heated with dehydrating agent

• stretching polyvinyl alcohol and then impregnating with iodine

In Young's double slit experiment if monochromatic light used is replaced by white light, then

• no fringes are observed

• only central fringe is white, all other fringes are coloured

• all bright fringes become white

• all bright fringes have colours between violet and red

Two coherent light beams of intensity I and 4I are superposed. The maximum and minimum possible intensities in the resulting beam are

• 9 I and I

• 9 I and 3 I

• 5 I and I

• 5 I and 3 I