Constructive interference (dark or bright)
Bright
Destructive interference (dark or bright)
dark
True or False: In constructive interference, two waves amplify each other to make a bigger wave.
True
If the path difference is a multiple (1lambda, lambda, 3lambda,..) of wavelength the interference is...
Constructive
If the path difference is an odd multiple of half the wavelength, the interference is...
destructive
The path difference for two waves interfering at a point is 3.5 times the wavelength of the wave. What type of interference is expected to occur?
Destructive
What two things must be valid for there to be interference of light?
The sources are coherent, which means that the waves they emit must maintain a constant phase with respect to one another.The waves have identical wavelengths.
For constructive interference, valid only if
phase difference is a result of the path difference:
(with any even multiple of pi)
1.
For destructive interference, valid only if
phase difference is the result of path difference:
(w/ odd multiple of pi)
In general, in order to have constructive interference, the waves must
be in phase
( (EVEN MULTIPLE OF PI)
to have destructive interference, they must be completely out of phase
() (ODD MULTIPLE OF PI).
What is Huygens’ principle and what does it
allow us to understand about light?
a. Huygens’ principle is a statement that all points of a wave front of light in a vacuum or transparent medium may be regarded as new sources of wavelets that expand in every direction . It allows us to understand and describe the wave nature of light and various optical phenomena such as reflection, refraction, interference and diffraction . b. “Each new point on the wave acts like a new source that generates. Spherical waves.” At slits c. The new wave is drawn tangent to the circular wavelets radiating from the point sources on the original wave front.
. According to Young's Double Slit Experiment, when the path lengths are equal..
The waves are in phase and undergo constructive interference at P
According to Young’s Double-Slit Experiment,
when the pathlengths differ by a wavelength…
The waves are in phase and undergo constructive
interference at Q
According to Young’s Double-Slit Experiment,
when the pathlengths differ by half a wavelength…
The waves are 180 degrees out of phase and
undergo destructive interference at R.
What is Young’s double slit experiment and what
does it show?
Young’s double slit experiment is an experiment
that shows light is a wave that can interfere and a particle that can be
detected.
What’s the
formula to find the path difference in young’s double slit experiment?
What's the formula for finding the location of the bright fringes in young's double slit experiment?
What's the formula for finding the location of the dark fringes in young's double slit experiment?
What’s the formula
for fining the width of each fringe?
a.
W=change in L /2d
How to find m=0?
a.
Central brightest
fringe
In young double slit experiment, L is the...
L is the distance from the double slit to the screen where the interference
pattern is observed in Young's double slit experiment
In young double slit experiment, d is the...
is the distance between the slits
Typically, in the double slit experiment, L is
Much greater than d
To find angular location of the bright and dark fringes...
a.
For bright: =mlambda.
For dark: =(m+1/2)lambda
For double-slit experiment, y tells you
Location of fringe from center fringe
For m=0 for dark fringes
It is the first dark fringe above the central bright fringe
How do you find the separation between two adjacent dark and bright fringes (assuming
they are the same size)
a.
Lambda(L)/d
b.
1.
If the distance
between the slits is doubled in Young's experiment, what happens to the width
of the central maximum?
W=change in L /2d The width is
halved. (see formula)
A Young's double-slit experiment is performed with three different colors of light: red, green, and blue. Rank the colors by the distance between adjacent bright fringes, from smallest to largest.
Red has the longest wavelength and blue the shortest so... Blue green red
In a double-slit experiment, when the wavelength of the light is increased, the interference pattern
Spreads out.
If a Young's double slit experiment carried out in air, is repeated in water, what happens to distance between the bright fringes?
Memorize this
formula find distance between fringes? (not on formula sheet)
Since it is a peak,
it is a constructive interference. For constructive interferences, path
difference is and m=2 so
the answer is two wavelengths