3. Introduction - About Microwave
Wavelength:
1 mm -1 m
Application:
Microwave oven
(2450MHz)
Transmission
Reference: https://commons.wikimedia.org/wiki/File:EM_Spectrum_Properties_edit.svg by NASA
4. Introduction - Michelson Interferometer
By moving the reflector on
the right side, it can change
the path difference to create
the constructive and
destructive interference at
the receiver.
This device also confirms
that aether does not exist.
5. Method - Michelson Interferometer
Move the reflector displacement
by 0.2 cm each. Simultaneously
record the data in Excel.
Continue this process until the
graph displays at least 11 peaks.
If there are n peaks, the
wavelength of the microwave is:
6. Result - Michelson Interferometer
λ max 1st 43.6 cm λ max
2.9 cm
λ max 11st 29.1 cm
λ min 1st 44.2 cm λ min
2.8727 cm
λ min 12nd 28.4 cm
7. Discussion - Michelson Interferometer
Reference: https://www.9x9.tw/mod/product/index.php?REQUEST_ID=55a65ce32a0f9d7015e5755b7e11e3b5d874ce6e2f5dc1dd76ccb2ed4e432ca9
https://www.irasutoya.com/2019/06/blog-post_87.html 、2006iPhO Q4
Read the scale by
bare eye?
Tool assistance?
8. Introduction - Thin Film Interference
By changing the angle of incidence ,
it alters the path difference in the
thin film, creating the constructive
and destructive interference at the
receiver.
This phenomenon can be observed
in soap bubbles, oil films, and
tempering colors on the steel.
Reference: https://commons.wikimedia.org/wiki/File:Tempering_standards_used_in_blacksmithing.JPG by Zaereth
9. Method - Thin Film Interference
Changing the angle of incidence
from 40 to 75 degree. According to
the relationship between the
receiver's current reading and the
angle of incidence of the thin film,
the minimum and maximum angles
for destructive and constructive
interference can be determined.
10. Method - Thin Film Interference
m: the order of interference
n: the refractive index
t: the thickness of thin film
11. Result - Thin Film Interference
t = (5.250 ± 0.050) cm
m = 5
n = 1.525 ± 0.038
13. Introduction - FTIR
When total internal reflection occurs, the
wave actually travels for a distance in the
air then back to the prism. This is called
the Goos-Hänchen shift.
When there are two prism made with the
same materiel, the wave will tunnel to the
other prism, known as frustrated total
internal reflection (FTIR).
Reference: 2006 IPhO Q4
14. Method - FTIR The intensity of the transmitted
wave decreases exponentially
with distance d.
Move the distance between two
prisms by 0.1 cm each. From 0.6
to 1.5 cm. (or current < 0.20 mA)
17. Introduction - Metal-rod lattice
In Bragg’s diffraction experiment, X-ray
are commonly used to explore crystal
structures.
However, in this experiment, we used
microwave to study the structure of the
metal-rod lattice because their
wavelengths are similar.
Reference: 2006 IPhO Q4
18. Method - Metal-rod lattice
In this experiment, assume
m=1 because only first order
diffraction can be observed in
the range of angles.
Bragg’s law:
19. Method - Metal-rod lattice
Changing the angle of incidence
from 20 to 50 degrees. The lattice
constant can be determined by the
Bragg’s law. Based on the
relationship between microwave's
intensity and the angle of
incidence of the lattice box.
23. Conclusion
1. The wavelength of microwave is 2.886 ± 0.028 (cm)
by Michelson Interferometer (wavelength)
2. The 5.25 cm Thin Film has refractive index n = 1.525 ± 0.038
by Thin Film Interference (interference)
3. The triangular prism has refractive index n = 1.534 ± 0.026
by Frustrated Total Internal Reflection (total reflection)
4. The metal-rod lattice box’s lattice constant a = 3.85 ± 0.13 (cm)
by Bragg’s diffraction (diffraction)
24. Reference & Acknowledgements
1.Diagram of the electromagnetic spectrum
Wikipedia contributors. (2024, April 27). Electromagnetic spectrum. In Wikipedia, The Free Encyclopedia. Retrieved 20:42, May 1, 2024, from
https://en.wikipedia.org/w/index.php?title=Electromagnetic_spectrum&oldid=1221002831
2.Tempering colors of steel
Wikipedia contributors. (2024, January 7). Thin-film interference. In Wikipedia, The Free Encyclopedia. Retrieved 20:44, May 1, 2024, from
https://en.wikipedia.org/w/index.php?title=Thin-film_interference&oldid=1194086122
3.Picture of fluorescent tape by 9x9
https://www.9x9.tw/mod/product/index.php?REQUEST_ID=55a65ce32a0f9d7015e5755b7e11e3b5d874ce6e2f5dc1dd76ccb2ed4e432ca9
4.Picture of magnifier
https://www.irasutoya.com/2019/06/blog-post_87.html
5.2006 iPhO Q4
https://ipho.olimpicos.net/pdf/IPhO_2006_Q4.pdf
6.2006 iPhO S4
https://ipho.olimpicos.net/pdf/IPhO_2006_S4.pdf
Thank you very much!!!
