1. The document is an optics laboratory note for a physics class at Baghdad University that provides 12 questions on topics in optics. 2. The questions cover concepts like Heisenberg's uncertainty principle, diffraction grating calculations, Michelson interferometer principles, Malus' law, Newton's rings experiment analysis, and definitions of optical phenomena like optical activity. 3. Students are instructed to answer 7 of the 12 questions in detail for the lab assignment.

1. Baghdad University – College of Science Second Semester
Dept. of Physics – 3rd Class A – Optics Laboratory Tue., April 2, 2013
Note: Answer seven questions only
1. Define Heisenberg's uncertainty principle. What is the particle on which it is applied?
Is it applicable on your mobile phone? Why?
2. Calculate how far the 1st order minimum is from the center of a diffraction pattern
produced using green laser of wavelength 533 nm incident normally on a 0.15 mm
wide single slit placed at 120 cm away from the screen.
3. For the 2nd order diffraction grating spectrum, you must have noticed that the spectral
lines are largely spaced as compared to the 1st order. Why is that?
4. The main principle of using Michelson’s interferometer to measure the refractive index
“n” of transparent medium of thickness “t” is……..
5. Give a definition to “Malus law” and plot the graphical relationship that satisfies it.
6. One 3rd class student obtained the following data table using 50 L/mm grating in the 2nd
order of Hg light spectrum:
Spectral line nm
Yellow 233.4 240.15
Will this student get high mark? Check it out in details.
7. Draw a schematic diagram of the wedge interference experiment indicating each part.
8. List the main similarities and differences between the zone plate and the convex lens.
9. In Newton’s rings experiment, the spacing between the second and third dark rings is
smaller than the spacing between the first and second dark rings. Why? Explain with
appropriate mathematical formula.
10.In the Newton rings arrangement, the radius of curvature of the curved surface is 50
cm. The radii of the 9th and 16th dark rings are 0.18 and 0.2235 cm, respectively.
Calculate the wavelength. [Answer: 505.49 nm].
11.Define the optical activity phenomenon. What are the parameters on which it depends?
Emphasize your answer with equations.
12.Do as required to five of the following:
 The interference coherent sources in the Newton’s rings are….
 Can sound waves be polarized? Why?
 The central fringe type and shape of the wedge is___,___, respectively.
 Why are the zones of the zone plate called “half – period zones”?
 Why does the grating exceed the single slit in forming diffraction spectra?
 The light source normally used in the polarimeter must be……due to……
 Give two optical phenomena (other than interference) you are being studied in the lab
that confirm the wave nature of the light.
 The refractive index can be measured by Newton’s rings where the final formula
is……
Good luck