Question

Numerical values of answers should have the quantities stated in each problem. values of answers should have the same number of significant digits as the numerical in each problem. Please include the appropriate SI unit in your answers.

 Values of universal constants: 

 2.) From the previous question, what is the phase difference between the lasers from different slits at the first dark fringe on the screen? 

Answer 1

As asked answer for Question 2-

Phase difference between interfering waves is odd multiple of π radians for destructive interference (dark fringe).

That is  

Where m = 0,1,2,3,4,5,6.......

For first dark fringe m=0

This gives radians

In degrees π radians = 180°