Interference - GRE Subject Test: Physics
Card 0 of 2
A double slit experiment is set up with the following parameters: two slits are a separated by a distance 
. A beam of light with wavelength 
shines through the two slits, and is projected onto a screen a distance 
from the slits. What is the distance on the screen between the central band and the next band on either side? (This distance is marked '
' on the figure).
A double slit experiment is set up with the following parameters: two slits are a separated by a distance
The condition for constructive interference with double slit diffraction is given by:
Where 
is 0, 1, 2, ...
Solving for the angle and using the small angle approximation, we get;
The distance 
in the diagram can be related to the other quantities by simple geometry:
Again, with the help of the small angle approximation. Setting the two thetas equal to each other and solving for 
, we get:
For the central band, 
, so the 
position is also zero. The next band, 
, yields a distance of:
The condition for constructive interference with double slit diffraction is given by:
Where
Solving for the angle and using the small angle approximation, we get;
The distance
Again, with the help of the small angle approximation. Setting the two thetas equal to each other and solving for
For the central band,
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Two waves with frequencies: 
are combined. What is the frequency of the resulting beat?
Two waves with frequencies:
The beat from two combined sound waves is:
The beat from two combined sound waves is:
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