4 - Interference, Diffraction and Polarisation Questions Answers
what is defination of polarization
Polarisation is the phenomenon to turn light in a particular direction by any means
for an aperture of size a illuminated by a parallel beam of light having wavelength λ the fresnel distance is
ans a^2/λ what is fresnel dist.??
fringe width β = λD/d
for β = d , D is called fresnel distance
so d2 = λD
so D = d2/ λ
now change d by a
A transparent sheet of paper of refractive index 'n' and thickness 't' is pasted on one of the slits in YDSE which uses monochromatic light of wavelength 'x' . How many fringes will cross through the centre if the paper is removed ?
total path difference created by the paper = (n-1)t
geometrical path difference = yd/D
so position of central maxima will be obtained by eq. (n-1)t = yd/D
here y is position of central bright, d is slit appeture and D is distance between slits and screen.
so y = (n-1)tD/d
width of maxima = xD/d , x is wavelength of light
so no. of fringes shifted = [(n-1)tD/d]/[xD/d] = (n-1)t/x