If a wave from one slit of a Young's double-slit set-up arrives at a point on the screen one-half wavelength behind the wave from the other slit, what is observed at that point?
a. dark fringe
c. gray fringe, neither dark nor bright
b. bright fringe
d. multi-colored fringe
Question 2
Interference effects observed in the early 1800s were instrumental in supporting a concept of the existence of which property of light?
a. electromagnetic character
c. wave nature
b. particle nature
d. polarization
