24 & 25
Intensity for an Unpolarized Beam
polarized light with an intensity of passes
through through a polarizer oriented at an angle to
the vertical. Find the transmitted intensity of the light for
Malus's Law :
the polarization experiment shown in the sketch, the final intensity
of the beam is .
What is the angle between
the transmission axes of the analyzer and polarizer?
need to find the factor so that I = which
Then set and
solve for .
the transmitted intensity for the following two cases: (a) A
vertically polarized beam of intensity passes
through a polarizer with its transmission axis at 60° to
the vertical. (b) A vertically polarized beam of intensity passes
through two polarizers, the first with its transmission axis
at 30° to the vertical, and the second with its transmission
axis at 60° to the vertical. In both cases, the final beam
is polarized at 60° to the vertical.
Using the Law of Malus:
Using the Law of Malus twice:
a set of three polarizers. Polarizer 1 has a vertical transmission
axis, and polarizer 3 has a horizontal transmission axis. Taken
together, polarizers 1 and 3 are a pair of crossed polarizers.
Polarizer 2, with a transmission angle at 45° to the vertical,
is placed between polarizers 1 and 3, as shown in figure. A beam
of umpolarized light shines on polarizer 1 from the left. Is
the transmission of light through the three polarizers (a) zero
or (b) nonzero?
The transmission is nonzero.