Question

A double slit apparatus is held 1.2 m from a screen.when red light (600nm) is sent through the double slit, the interference pattern on the screen shows a distance of 12.5 cm between the first and tenth fringes. what is the separation of the slits?
my answer: d=5.18x10^-5m

b) what will be the difference in path length for the waves travelling from each slit to the tenth nodal line?

Answer 1

Correct

Answer 2

do you know the answer for b?

Answer 3

If the distance of tenth nodal line from the zeroth maximum is z than use Pythagoras theorem:
path diff = \[\sqrt{D ^{2}+z ^{2}} - D\]
where D is the distance of the slits to the (fringe- ) screen