1. During lab this week the interference pattern of a double slit set up was investigated. The criterion for the nth bright spot as counted from either side of the central maximum is, sinθn = nλ/d.
Describe how the interference pattern would be affected in the following two scenarios:
a. blue laser light were used instead of red
b. the slits were moved farther apart
2. Consider laser light passing through a single narrow slit. What happens to the width of the central maximum of the diffraction pattern if the slit were now half as wide?
Destructive Interference for the first dark spot can be determined by the equations below.
In the first equation, θdark is the angle to the first dark fringe, λ is the wavelength of laser light, and W is the slit width. In the second equation, y is the height of the first dark fringe and L is the distance from the slit to the screen. Use small angle approximation to explain.
Wsin(θdark) = λ
tan(θdark) = y/L
