Chapter 24, Problem 5P

To determine

The separation of the two slits.

Answer to Problem 5P

The answer is $1.43m$ .

Explanation of Solution

Given info:

distance from slits to the screen,  $L=2m$

the distance between the fringes, $y=38mm=0.038m$

Integer,  $m=4$

Wavelength, $\lambda =680nm=6.8\times {10}^{-7}m$

Formula used:

It is known that $d=\frac{m\lambda L}{y}$

  $m$ is an integer

  $\lambda$ is wavelength

  $L$ is distance from slits to the screen.

  $d$ is a distance between slits

  $y$ is the distance between the fringes 

Calculation:

Substitute the values in formula $d=\frac{m\lambda L}{y}$ ,

  $d=\frac{4\left(6.8\times {10}^{-7}m\right)2m}{.038m}=1.43m$

Conclusion: The required value is $1.43m$ .