Wave OpticsHard
Question
Light of wavelength 6000 
is reflected at nearly normal incidence from a soap films of refractive index 1.4. The least thickness of the film that will appear black is :
is reflected at nearly normal incidence from a soap films of refractive index 1.4. The least thickness of the film that will appear black is :Options
A.infinity
B.200
C.2000
D.1000
Solution
Soap film Interference pccure occure between two reflected rays A and B is reflected from upper surface and B is reflected from lower surface.
The path difference between the two becomes 2μt +
If it is equal to
then destructive interference ocdcurs and we see dark fringes fromabove. So the equation 2μt + = give the least value of t for which we see dark fringes.2μt = λ ⇒ t =
≅ 2000 Create a free account to view solution
View Solution FreeMore Wave Optics Questions
When a ray of light enters a glass slab, then...Figure shows plane waves refracted from air water using Huygen′s principle a, b, c, d, e, are lengths on the diagr...A very thin transparent film of soap solution (thickness → 0) is seen under reflection of white light. Then the co...In a negative zone plate :...In Young′s double slit experiment, the slits are 2 mm apart and are illuminated by photons of two wavelengths _...