When a beam of white light is passed through sodium vapours and then through a spectrometer, spectrum so obtained has two dark lines present in the yellow region. this spectrum is called:
band spectrum
continuous spectrum
absorption spectrum of sodium
absorption spectrum of sodium
C.
absorption spectrum of sodium
(i) What is the difference between polarised light unpolarised light based on the direction of electric vector E?
(ii) What will be the effect on the width of the central bright fringe in the diffraction pattern of a single slit if :
(1) Monochromatic light of smaller wavelength is used.
(2) Slit is made narrower.
(ii)
1. Width will decrease
2. When slit is made narrower the central bright fringe becomes wider.
With the help of a labelled diagram, show that fringe separation β in Young’s double slit experiment is given by:
where the terms have their usual meaning.
Let S be a narrow slit luminated by monochromatic light, S1 and S2 be two parallel narrow slits very close to each other.
The light waves S reach S1 and S2 in some phase. According to Higgens principle S1 and S2 etc as new light sources from which secondary wavelet originate. These wavelet originate. These wavelets form interference fringes on screen.
Let a bright fringes be formed at P
Path difference. = (S2P - S1P)
ΔS2P - S1P = S2P - AP = S2A
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