Question

Hi, I'm new and really struggling with this question: Monochromatic light with a wavelength of 6.4 E -7 meter passes through two narrow slits, producing an interference pattern on a screen 4.0 meters away. The first order bright band lines are 2.0 E -2 meters away from the central bright maxima.
What is the distance between the slits?

Answer 1

That is the Young interference. So we have to apply this formula:
\[\large d\sin \varphi = \lambda \]
where d is the requested distance, and:
\[\large \sin \varphi \cong \frac{{2 \times {{10}^{ - 2}}}}{4} = ...?\]

Answer 2

and \[\large \lambda \]
is the wavelength of the employed radiation