Question

The distance between the slits is 0.7 mm

The diagram above shows the pattern of interference fringes for light of wavelength lambda = K ____________ times 10^-7 m, passing through two narrow slits, projected onto a screen a distance of L _____________ m away. Use a ruler to measure the distance between bright fringes on the diagram, and then determine the distance between the two slits. So... what is the distance between the two slits? Answer: ______ times 10 m

Answer 1

$\lambda$ = wavelength = 5.5 x 10^-7 m

D = screen distance = 3.3 m

w = distance between bright fringes

d = slit width

distance between bright fringes is given as

w = D $\lambda$ /d

d = D $\lambda$ /w

d = (3.3) (5.5 x 10^-7 )/w = (18.2 x 10^-7 )/w