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)
Grades
Lab report (20 pts)
• Reading quizzes: 5 pts
• Experiment, Data, observation: 10 pts
• Discussion / Conclusion: 3 pts
• Participation: 2 pts
Final Test: 20 pts
Lab 2
Spectroscopy
Lab 2: spectroscopy
Prism
Dispersion of visible
light into a spectrum
Rainbow
Dispersion of sunlight
by raindrops in sky
Lab 2: spectroscopy
Lab 2: spectroscopy
Speed of light
c

T
c  3 108 m / s
period
wavelength
wavenumber
k
Energy
E 
Planck’s constant
 1.05 1034 Js
2

momentum
(cyclic
wavenumber)
k 
p k
1

Lab 2: spectroscopy
A. Qualitative observations
• L2. 1: Hand-held spectroscope
B. Calibration
• L2.2: Acquire spectrum of He gas lamp
• L2.3: Identify lines and calibrate
(convert pixels into wavelength numbers)
• L2.4: Check new spectrum
Lab 2: spectroscopy
Helium emission spectrum
Lab 2: spectroscopy
C. Hydrogen emission • L2.5: Acquire spectrum of H gas spectrum
2
• L2.6: Identify 4 Balmer- visible lines
• L2.7: compare with literature
• L2.8: retrieve the quantum numbers ni
D. Incandescent lamp
• L2.9: Acquire spectrum of incandescent light bulb
• L2.10: Compare to black body spectrum
and estimate the temperature of the bulb
E. Fluorescent lamp
• L2.11: Acquire spectrum of fluorescent lighting panel
• L2.12: Compare to spectrum to literature
• L2.13: Extrapolate spectrum to black-body emission
• L2.14: Acquire spectrum of LED (flashlight)
Lab 2: spectroscopy
Hydrogen emission spectrum
Balmer visible series
0
E
Energy transition
Paschen
 1
1 

E 
 E1 2  2
n


 i nf 
hc
E4
E3
E2
Balmer
 1
1 

R 2  2
n


 f ni 
1
Rydberg constant
Lyman
E1
Lab 2: spectroscopy
Quantum statistical mechanics
Black-body spectrum
Wien displacement law
Bosons
at equilibrium T
2.9 10 nm.K

T
6
Analogy: lava emits light when hot !
Lab 2: spectroscopy
Fluorescent lamp