http://phet.colorado.edu/en/simulation/legacy/wave-interference This question is
ID: 1437656 • Letter: H
Question
http://phet.colorado.edu/en/simulation/legacy/wave-interference
This question is based on the images in the link above. It is a simulation questions... I am not sure if I am using the simulation correctly.
"Wave Interference" simulation. Click on the "Light" tab at the top. Start the simulation by making sure the button for pulse (on the light bulb) is selected and by clicking on the play button at the bottom of the window.
Click the "Add Mirror" button. Position the mirror along the vertical direction and as far away from the light source as possible (without getting out of the region that shows the light waves). What happens to the light waves when they reach the mirror?
A. Nothing; they simply continue to travel through the mirror.
B. The light waves are reflected back from the mirror and do not interfere with the waves traveling toward the mirror.
C. The light waves are reflected back from the mirror and interfere with the waves traveling toward the mirror.
Remove the mirror by right-clicking on it. Select the "Two Lights" button and look at the light waves from the two light bulbs traveling through space. What do the "dark" regions in the pattern formed by the two interfering light waves represent?
A. Constructive interference of light waves
B. Destructive interference of light waves
C. Dispersion of light waves
D. Convergence of light wave
stop the simulation and select "One Light." Select a green light (that has a wavelength between 495–570 nm). Also select "Two Slits" with approximately the following settings: 525 nm for the slit width, 1,968.75 nm (the third line) for the Barrier Location, and select 2625 nm for the Slit Separation. Click on the "Show Screen" button and then click on the "Intensity Graph" button. These windows will allow you to "see" the interference pattern of the two traveling light waves on the screen as well as the graph of the intensity of light in the interference pattern.
The slider in the left side of the simulation window allows you to change the amplitude of the light wave emitted by the light bulb. What happens to the intensity of the central bright fringe if the amplitude of the light wave is increased?
A. It decreases.
B. It increases.
C. It stays the same.
By clicking the two-slit barrier and dragging it, you can change its position. Always allow a few seconds for the simulation to catch up with the changes you are making before analyzing the results. When the two-slit barrier is brought closer to the screen (and farther away from the source), what happens to the distance between two adjacent bright (or dark) fringes?
A. It becomes larger.
B. It becomes smaller.
C. It stays the same.
Bring the two-slit barrier back to the 1,968.75 nm (the third line) position. Slowly decrease the slit separation. What happens to the distance between two adjacent bright (or dark) fringes?
A. It becomes smaller.
B. It becomes larger.
C. It stays the same.
Explanation / Answer
1)
The light rays gets reflected from the mirror, since they are in phase with the waves that are coming towards the mirror, the can interfere with them. Thus, he light waves are reflected back from the mirror and interfere with the waves traveling toward the mirror.
2)The interference of crests of first wave with the troughs of the second wave or crests of the second wave with the troughs of the first wave causes dark bands in the interfrence pattern and we call this interfrence as destructive interfrence.
3) The intensity is directly proprtional to the square of the amplitude. Thus, the increase in amplitude causes an increase in intensity.
4) The distnace between adjacent fringes is directly preportional to the distance between slits and screen. Thus, the distance between two adjacent bright (or dark) fringes becomes smaller with the decrease in the distance between slits and screen.
5)he distnace between adjacent fringes is inversly preportional to the slit seperation. Thus, the distance between two adjacent bright (or dark) fringes becomes larger with the decrease in the slit seperation
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.