1. For diffraction from a single slit:
a. the space between adjacent minima on either side of the central
maxima is given by the expression:
Dx = Ll/a
where L is the distance from the slit to the viewing screen, l
is the wavelength of the light and a is the width of the slit; and
b. the intensity of the light in the diffraction pattern as a
function of the angle q is given by the expression:
Iq = Imax[ (sin q)/q]2
where a = (p a q) /
l .
2. For interference and diffraction from a double slit:
a. the location of the maxima are given by the expression:
x = (nlL)/d
where n is the number of the maxima, l is the wavelength of the
light, L is the distance from the slit to the viewing screen and d
is the slit spacing; and
b. the intensity of the light in the interference and diffraction
pattern as a function of the angle q is given by the expression:
Iq = Imaxcos 2 b
where b = (p d q)/l .
3. For a multiple slit system:
a. the maxima and minima locations for the envelope are due to
diffraction effects and are described mathematically by the appropriate
equations above; and
b. the intensity of the light in the interference and diffraction
pattern as a function of the angle q is given by the expression:
Iq = (Imax/N2) [(sin Nb)/sin b]2 [(sin a)/a]2
where N is the number of slits.
In this lab, the students experimentally confirm the validity of the following:
