Computer simulation. This question uses the PhET simulation.
Follow these instructions carefully. Go to
http://phet.colorado.edu/en/simulation/wave-interference, choose
the 'light' tab, 'one light' and select 'two slits', and click
'show screen'. Set the 'Slit Width' to one tick above 0 nm, and
increase the light source amplitude to the maximum value. Set the
barrier location to 2590 and the slit separation to one tick below
1750.
Using violet light, what happens in the simulation if
you increase the distance between the two slits? Choose 3 correct
answers.
a) The distance between bright fringes decreases.
b) Less fringes appear on the screen.
c) The distance between bright fringes increases.
d) More fringes appear on the screen.
e) The distance from the central maximum to the first fringe decreases.
f) The distance from the central maximum to the first fringe increases.
Using violet light, what happens in the simulation if
you move the two slits closer to the screen by increasing 'Barrier
Location' (i.e., you decrease L)? Choose 3 correct
answers.
a) The distance between bright fringes decreases.
b) Less fringes appear on the screen.
c) The distance from the central maximum to the first fringe decreases.
d) More fringes appear on the screen.
e) The distance between bright fringes increases.
f) The distance from the central maximum to the first fringe increases.