Physics 145
Introduction to Experimental Physics I
Instructor: Karine Chesnel
Office: N319 ESC
Tel: 801- 422-5687
kchesnel@byu.edu
Office hours: on appointment
Class website:
http://www.physics.byu.edu/faculty/chesnel/physics145.aspx
Lab space availability
Wednesday 3 – 6 pm:
3 seats
Thursday 8 – 11 am:
1 seat
Thursday 11 am– 2 pm:
1 seat
Thursday 3 – 6 pm:
-
Friday 11am – 2 pm:
9 seats
Friday 2 – 5 pm:
-
Your lab assignments
1. Prepare by reading the introduction material
2. Answer quiz questions (within the first half hour) and
submit the sheet to your TA
3. Proceed to the experiments: L2.1, L2.2, etc…
4. Write a report of your findings for each experiment,
in your lab notebook (individual reports)
Lab 3
Interference
Diffraction
Interferences
Adding waves:
Constructive
interference
Destructive
interference
Difference in optical path:
𝑛l
1
∆ = 𝑑𝑠𝑖𝑛𝜃 =
l
𝑛+
2
constructive
destructive
Interferences & diffraction
Diffraction pattern
Single slit
Interferences & diffraction
Diffraction pattern
Double slits
Interferences & diffraction
Double slits
Envelope width
(separation between maxima)
Slits width
Peak separation
Slits separation
Interferences & diffraction
Single slit
Double slits
Interferences & diffraction
Double slits
Five slits
Interferences & diffraction
Grating
second order
first order
Zero order
first order
second order
Lab 3: Interference & Diffraction
A. Alignment
• L3. 1: Vertical alignment (posts)
• L3.2: Horizontal alignment (bench)
• L3.3: Lenses positioning (collimation, focalization)
• L3.4: Source – eyepiece alignment
Lab 2: spectroscopy
B. Qualitative observations
• L3.5: Green filter – Single slit, varying size
• L3.6: Try different filters, optimize color
• L3.7: Double-slits, varying spacing
• L3.8: Grating: compare intensity, resolution
C. Quantitative measurement
• L3.9: Use diffraction pattern from the grating
to determine the wavelength of the light