PHYS S271 Discovering Physics

Assignment 04 (Cut -off date 25 Apr 2022)
Use A4-size paper for your written assignments, and put your name, your student number, andtheassignment number at the top of every sheet. When you have completed your written assignments, you should submit a pdf copyof yourassignment via the e-submission functions in OLE. For general instruction about the e-submission of assignment, you should refer to e-submissioninstructions. In applying for late submission, please make an online application on or before thecut-offdate in the OLE. Any late submission without prior approval will not be accepted. Remember that the cut-off date is the last date by which your assignment is submittedviathee-submission in OLE. Normally any late submission for an Assignment is not appreciated and approval of late submissionisnot automatically granted. I would like to remind you of the need to submit your assignment intime.
PHYS S271 Assignment 04 (2021)
Cut-off date: 25 Apr 2022
You should submit your completed assignment via e-submission in OLE no later than Monday, 25Apr2022. According to the University’s assessment regulations, there is no extension for this assignment.Online Laboratory Work Assignment
You should watch the videos of the online laboratory activities in OLE and study the LongLabmanuals. The attendance of your online laboratory activities will be monitored. Question 1 (Videos 1A Microwave, Experiment 1A in Lab Manual )
This question carries 45 % of marks
(a) Watch the videos on Reflection and study Lab manual 1A Microwave. The following data are obtained from the experiment on Reflection. Angle r / degree Detector Meter Reading / mA
0 0.02
10 0.07
20 0.5
30 1.5
40 2
50 1.6
60 0.85
Table Q1a
Angle of incidence in = 40. (i) Obtain a plot of angle r vs detector meter reading using Excel. (5marks)(ii) From your graph, find the angle of reflection. (3marks)(iii) Is it consistent with the law of reflection in optics? Justify your answer. (2marks)(iv) Why are reflected microwaves observed for a range of values of angle r?
(b) Watch the videos on Dif raction and study Lab manual 1A Microwave. The following data are obtained from the experiment on Diffraction. Angle  /degree Detector Meter Reading /mA
50 0.06
40 0.29
30 0.33
20 0.06
10 0.3
0 0.59
-10 0.18
-20 0.08
-30 0.37
-40 0.22
-50 0.06
Table Q1b
The wavelength of the microwave used in the experiment is 2.8 cm. The width of the double slits used in the experiment is 5 cm. (i) Obtain a plot of angle  vs detector meter reading using Excel. (5marks)(ii) From your graph find the angles at which maximum diffractions occur. (3marks)(iii) Are your results consistent with double-slit diffraction formula, d sinn =n?Justifyyour answer. (4marks)(iv) Another double slit of slit separation 40 mm is provided. Can you predict the positionsof maximum diffraction?
(c) Watch the videos on Polarization and study Lab manual 1A Microwave. The following data are obtained from the experiment on Polarization. θ / degree Detector Metre Reading / mA
0 0.36
10 0.32
20 0.3
30 0.25
40 0.5
50 1
60 1.64
70 2.92
80 3.8
90 4.23
Table Q1c
(i) Obtain a plot of angle  vs detector meter reading using Excel. (5marks)(ii) The source horn emits microwave polarized vertically. The detector only receivesthevertically polarized wave. How could you confirm this statement experimentally?(5marks)(iii) From the polarization graph, we notice that when the grid wires are vertical, nomicrowave is transmitted through the grid. Explain why?
Question 2 (Videos on 2 Electrical Oscillation, Oscillation in LC Circuits in Labmanual )This question carries 25 % of marks
Watch the videos on Electrical Oscillation and study Oscillation in LC Circuits in Lab manual. The following data are obtained from the experiment on Resonance on LC circuits. Oscillator Frequency (kHz) Amplitude of VLC(mV) Amplitude of VLC(mV) with10Ω10 2 2
15 4.3 4.4
16 5 5.2
17 6.2 6.2
18 8.6 7.6
19 10.6 9.7
20 17.6 14
21 31.6 18.2
22 121 20.8
23 52.4 19
24 24 16
30 5.6 5.8
35 3.7 3.7
Table Q2
C = 0.1 F
(a) Obtain a plot of Amplitude of VLC against oscillator frequency using Excel. (5marks)(b) Obtain another plot of Amplitude of VLC with 10 Ω against oscillator frequency onthesamegraph in (a) using Excel. (5marks)(c) What is the resonance frequency as measured from this experiment? (4marks)(d) Using an appropriate formula, work out the theoretical resonance frequency of the resonancecircuit. Take the inductance of the coil equal to L = 541  H for your calculationoftheresonance frequency of the circuit (5marks)(e) Explain why there is a difference in the widths of the two resonance curves. (6marks)
Question 3 (Videos on 3B Newton’s Rings, Newton’s Rings in Lab manual )
This question carries 30 % of marks
Watch the videos Newton’s Rings and study Newton’s Rings in Lab manual. The following data are obtained from the experiments on Newton’s Rings. n 1st Reading/m 2nd Reading/m Diameter D Radius, r r
1 4.62 2.05 2.57 1.285 1.651225
2 5 1.75 3.25 1.625 2.640625
3 5.21 1.5 3.71 1.855 3.441025
4 5.4 1.3 4.1 2.05 4.2025
5 5.61 1.11 4.5 2.25 5.0625
6 5.78 0.93 4.85 2.425 5.880625
7 5.93 0.78 5.15 2.575 6.630625
Table Q3
The radius of the lens, R = 1.3m
(a) Obtain a plot of r
2 against n using Excel. (6marks)(b) Find the slope of the graph. (3marks)(c) Calculate the average wavelength of sodium light. (3marks)(d) Destructive interference occurs when the two reflected waves are exactly out of phase. What isthen the condition for destructive interference? (6marks)(e) State the colour of the central region of the ring system. Explain your statement. (7marks)(f) In this experiment, diameters are measured instead of measuring the radii of the ringsystem. Explain why. (5marks)(g) What would happen, if instead of using a sodium light source, we use an ordinary light source?(5marks)[ End of Assignment 04 ]

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