Classes
Class 9Class 10First YearSecond Year
$20. In an interference patterna) Bright fringes are wider than dark fringesb) Dark fringes are wider than bright fringec) Both dark and bright fringes are of equal widthd) Central fringes are brighter than the outer fringes$

$9.1 Under what conditions two or more sources of light behave as coherent sources?$

$9.6 A light is incident normally on a grating which has 2500 lines per centimetre. Compute the wavelength of a spectral line for which the deviation in second order is 15.0^{\circ} .$

$15. When crest of one wave falls over the trough of the other wave this phenomenon is known asa) Polarizationb) Constructive interferencec) Destructive interferenced) Diffraction$

$77. When a soap film (or oil film) on water is observed in day light it exhibits beautiful colours due to:a) Dispersionb) Refractionc) Reflectiond) Interference$

$22. The blue to the sky is due toa) Diffractionb) Reflectionc) Polarizationd) Scattering$

$52. Which of the following demonstrates that light waves are transverse waves?a) Interferenceb) Polarizationc) Diffractiond) Reflection$