badge image

Enroll For Free Now & Improve Your Performance.

User Icon
User Icon
User Icon
User Icon
User Icon

Thank you for registering.

One of our academic counsellors will contact you within 1 working day.

Please check your email for login details.

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

Total Price: Rs.

There are no items in this cart.
Continue Shopping
Grade: 11


Two coherent point sources S 1 and S 2 vibrating in phase emit light of wavelength λ. The separation between the sources is 2λ. Consider a line passing through S 2 and perpendicular to the line S 1 S 2 . What is the smallest distance from S 2 where a minimum of intensity occurs?

11 years ago

Answers : (1)

Askiitians Expert Bharath-IITD
23 Points

Dear Sundeep,

See the diagram given below:



Now we know that if I1and I2 are the intensities of the given two coherent sources of light.


resultant I = I1 + I2 + 2 √(I1I2) cos δ

δ = phase difference between the two waves coming from the two sources

tan δ = 2λ/y....................1

and also

cos δ = x/2λ.........................2

 where x is the path difference between the waves and y is the distance along S2 at which  I is minimum

So phase difference must be odd multiples of π

so δ = (2m+1) π

and δ = x * 2π/ λ

         From 2 and above equation we get cos θ = (2m+1)/4  where θ  is shown in the figure

for first minima


so cos θ = 1/4

tan θ = √15

and from 1

y = 2λ/√15

is the distance at which we get first minima  

11 years ago
Think You Can Provide A Better Answer ?
Answer & Earn Cool Goodies

Course Features

  • 101 Video Lectures
  • Revision Notes
  • Previous Year Papers
  • Mind Map
  • Study Planner
  • NCERT Solutions
  • Discussion Forum
  • Test paper with Video Solution

Course Features

  • 110 Video Lectures
  • Revision Notes
  • Test paper with Video Solution
  • Mind Map
  • Study Planner
  • NCERT Solutions
  • Discussion Forum
  • Previous Year Exam Questions

Ask Experts

Have any Question? Ask Experts

Post Question

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