Student Responses to Reading Quiz #14, due Wednesday March 3
Question 1: In a previous class, we discussed how two sources of phase difference were path length difference and phase difference introduced at the source. What are two (2) OTHER sources of phase difference?
1. 1. When it reflects off of a boundary 2. Reflection off of a point where the density increases suddenly
2. Another cause of phase change is the 180 degree phase change of a reflection from a boundary surface. A final source of pase difference is diffraction
3. Another source of a phase difference is when a wave reflects off a boundary and undergoes a 180 degree phase change. As we saw in one of our homework problems we also can have a phase difference when waves are separated by some amount of time.
4. two reasons for phase change, are reflection and if they are nhot coherent.
5. 1. Phase difference can be caused by the 180 degree phase change a wave may undergo due to reflection from a boundary surface. 2. Phase difference can also occur because of the interference of waves from two sources that are not coherent
6. Reflection off of a boundary surface and interference also cause phase differenc
7. Phase difference can be created when a wave is reflected off a boundary. This creates a 180-degree phase change. There is a 180-degree phase change when light travels into a medium in which it moves slower.
8. Phase difference can arise from the 180 degree phase change a wave sometimes undergoes when reflecting off a boundary surface, or from multiple slit setups.
9. Phase difference can occur from reflection from a boundary surface or diffraction through two slits.
10. 1) 180 degree phase change due to reflection from a boundary surface 2) Interference from waves from sources that are not coherent
11. A phase difference can occur from a reflection of a wave, like the 180 phase difference that occurs when a wave is reflected from a fixed point on a string. Phase difference can also occur when one light beam is split into two beams.
12. - The 180 phase change a wave undergoes upon reflection from a boundary surface. - Incoherence of sources
13. Reflection, which sometimes induces a pi/rad shift in phase, and diffraction at two seperate locations..
14. When a wave reflects off of a boundary, it can undergo a 180 degree phase change. Another source of phase difference is noncoherent wave sources.
15. 1) reflection from a boundary surface 2)reflecting light from
Question 2: When a light wave goes from a medium of low index of refraction to a medium of high index of refraction, the light wave slows down (for example, air into water). What happens to the WAVELENGTH of the light wave?
1. The wavelength remains constant, a phase change of 180 degrees occurs
2. When light goes from a medium of low index of refraction to a medium of high index of refraction, the wavelength will become shorter.
3. The wavelength of the wave would decrease.
4. n can't be less than one so the new wavelength is smaller
5. The wavelength of the light will become smaller because it is being divided by a larger number, the high index of refraction.
6. The wavelength of the wave decreases because the velocity decreases, thus the product of wavelength and frequency decrease and frequency remains constant.
7. The wavelength becomes smaller. You get the new wavelength by dividing the old wavelength by the index of refraction, which is always greater than one.
8. The wavelength of the light wave decreases. The new wavelength is equal to the old wavelength divided by the index of refraction.
9. Since v is proportional to wavelength, the wavelength also decreases.
10. The wavelength decreases. When a wave goes from one medium to another, the new wavelength equals the old wavelength divided by the index of refraction of the new medium.
11. The wavelength gets smaller. The new wavelength equals the original divided by the index of refraction.
12. v is decreasing, so wavelength is decreasing (frequency is fixed)
13. It decreases by a factor of the index of refraction.
14. The wavelength gets smaller. The new wavelength is (lambda initial)/n, where n is the index of refraction of the new medium.
15. The wavelength decreases.
Question 3: Look over your lab manual and notebook for Experiment 17: Interference of Light. Which of the phenomena that you observed in that lab did you find the most intriguing?
1. Using Light interference to determine the air pockets between to pieces of glass
2. What I found most interesting is that a larger obstruction produced a smaller diffraction.
3. I simply liked the part on diffraction because it is completely counter-intuitive. You would never expect if you passed light through a tiny slit that it would spread out in a specific pattern. Its interesting that you observe the same effects whether or not you pass light through a small slit or it passes around an obstruction, such as a piece of hair.
4. I thought that the air wedges were interesting, because they depended on the pressure
5. I found the pattern that resulted from shining the laser through the diffraction grating to be the most intriguing, because it was not as symmetrical and perfect as the patterns that resulted from shining the laser through slits.
6. I found it intriguing that increasing the number of slits adds a number of sub-dots to the interference pattern in between the larger dots.
7. I thought it was interesting that you can use air wedges to find the flatness of glass plates. Straight fringe patterns indicate flat glass.
8. The secondary maxima that resulted from the 3-, 4-, and 5-slit slides were rather intriguing.
9. The fringe patterns between peices of glass.
10. The whole contour map thing created by the air wedges between the two slides that you could see when shining light on it. I don't know, it was all interesting I guess. I just thought the air wedge thing was crazy.
11. The fring lines that shifted with pressure between the two sheets of glass were most interesting.
12. Inteference pattern of 2,3, many slits
13. The "ghost lights" that appeared when one looked through the grating at the coherent beam.
14. I was intrigued by the interference patterns produced by 4 and 5 slits, because those had more complexity than the others.
15. I think the seemingly random event that occured from using the laser on the slits
Question 4: What are the conceptual and mathematical issues from the reading that you would like to discuss in class?'
1. I'm lost by almost all of this. I hope to be able to pick it up in class on Wednesday
2.
3. The section on film interference was confusing
4.
5. most of it seemed to be a review from the lab
6. Clarify exactly how the 'virtual slit' works
7. I found this reading difficult. It's hard to be specific, but going over a problem like example 35-2 might help. This is the example with a slip of paper in between two peices of glass and you have to calculate the interference fringe/centimeter.
8. Newton's rings
9. Exactly the why of interference in thin films.
10.
11.
12. Calculating single/two-slit(s) diffraction pattern. (35-5)
13. None, really.
14. none
15.
Question 5: What concerns or issues do you still have with material from previous classes?
1. None as of yet
2.
3. None
4.
5. none
6. Waves r phun
7.
8. None
9. None.
10.
11.
12. n/a
13. None, really.
14. none
15.