Answer:
The number of bright fringes per unit width on the screen is, [tex]x=\dfrac{\lambda D}{d}[/tex]
Explanation:
If d is the separation between slits, D is the distance between the slit and the screen and [tex]\lambda[/tex] is the wavelength of the light. Let x is the number of bright fringes per unit width on the screen is given by :
[tex]x=\dfrac{n\lambda D}{d}[/tex]
[tex]\lambda[/tex] is the wavelength
n is the order
If n = 1,
[tex]x=\dfrac{\lambda D}{d}[/tex]
So, the the number of bright fringes per unit width on the screen is [tex]\dfrac{\lambda D}{d}[/tex]. Hence, the correct option is (B).
