MY CART (5)

Use Coupon: CART20 and get 20% off on all online Study Material

ITEM
DETAILS
MRP
DISCOUNT
FINAL PRICE
Total Price: R

There are no items in this cart.
Continue Shopping
Menu
rajesh saini Grade:
        

what will happen to shape of fringes when we use slits instead of pin holes in young experiment for interference?

6 years ago

Answers : (1)

SAGAR SINGH - IIT DELHI
879 Points
										

Dear student,


Shape will be circular........



A train of plane light waves is incident on a barrier containing two narrow slits separated by a distance’d’. The widths of the slits are small compared with wavelength of the light used, so that interference occurs in the region where the light from S1 overlaps that from S2.


1915_Deubleslit.JPG


 


A series of alternately bright and dark bands can be observed on a screen placed in this region of overlap.


The variation in light intensity along the screen near the centre O shown in the figure


226_fringe-width.JPG


 


Now consider a point P on the screen. The phase difference between the waves at P is θ, where


θ= 2π/λ ΔPo


(where ΔPo is optical path difference, ΔPo=ΔPg; ΔPg  being the geometrical path difference.)


 1679_YOUNG’S DOUBLE SLIT EXPERIMENT.JPG


 


= 2π/λ  [ S2P - S1P ] (here λ = 1 in air)


As     As, D >> d,

S2P - S1P ≈  λ d sinθ


sin θλ ≈ tanθ( = y/D).


[for very small θ]


 Thus, θ = 2π/λ (dy/D)


For constructive interference,

θ = 2nλ    (n = 0, 1, 2...)


⇒  2π/λ (dy/D) = 2nπ     ⇒ y = n λD/d


Similarly for destructive interference,

y = (2n - 1) λD/2d  (n = 1, 2 ...)


 



















Please feel free to ask your queries here. We are all IITians and here to help you in your IIT JEE preparation.


All the best.


Win exciting gifts by answering the questions on Discussion Forum. So help discuss any query on askiitians forum and become an Elite Expert League askiitian.


Now you score 5+15 POINTS by uploading your Pic and Downloading the Askiitians Toolbar  respectively : Click here to download the toolbar..


 


Askiitians Expert


Sagar Singh


B.Tech, IIT Delhi



















6 years ago
Think You Can Provide A Better Answer ?
Answer & Earn Cool Goodies
  • Complete Physics Course - Class 12
  • OFFERED PRICE: R 2,600
  • View Details
Get extra R 520 off
USE CODE: CART20
  • Complete Physics Course - Class 11
  • OFFERED PRICE: R 2,800
  • View Details
Get extra R 560 off
USE CODE: CART20

Ask Experts

Have any Question? Ask Experts

Post Question

 
 
Answer ‘n’ Earn
Attractive Gift
Vouchers
To Win!!! Click Here for details