Light: Double slit experiment
What is Thomas Young's Experiment double slit experiment? Why is this experiment important?
In 1801 Thomas Young, an English physicist, performed an experiment that forever confirmed that light was composed of waves.
In this experiment he allowed light from a single source to be split into two beams by using a pair of closely spaced slits.
What occured when the light passed through these slits gave unrefutable evidence of the wave-like character of light.
First, the light from each slit diffracted, spreading out past the slits and then overlapped with light from the other slit
as iit reached
the screen.
The pattern on the screen was a classic interference pattern. It was not a pattern showing just two bright areas, but a pattern
showing a series of alternating bright and dark fringes that were symmetrical on each side of a bright central fringe.
This was important because this experiment caused an increased interest in understanding light based upon a wave theory,
as opposed to the corpuscular (or particle) theory that was proposed by Isaac Newton.
The production of a diffraction-interference pattern is due to the difference in path lengths of the light traveling
from each of the slits to points on the screen. When the path
difference from the two slits to a point on the screen is an integral number of wavelengths, e.g., 1, 2, 3 wavelengths, the interference is
constructive and
produces a bright fringe at that point.
On the other hand, when the path
difference from the two slits to a point on the screen is an integral number of wavelengths plus half a wavelength, e.g., 0.5, 1.5, 2.5
wavelengths, the inteference of the two beams is destructive and results in a dark fringe at that point.
Experiment with the simulation below to develop an understanding of the relationship between path difference, phase,
and the type of interference that occurs at various fringes in the Thomas Young's Double Slit Experiment. Move the horizontal slider
to look at different fringes and note the wavelength difference (indicated by the blue arrow next to the slits) between the two beam paths.
Below is the experimental setup of the Thomas Young's Double Slit experiment. It allows the used to change the separation of the slits, and the color of the light used in the experiment and shows the resulting interference pattern. Notice the effect on the pattern as changes are made to these parameters.
Experiment with this simulation to develop a more thorough understanding of the Thomas Young's Interference experiment.
Use the above simulation to answer the following questions?