Lab 15: Activ Physics on Lasers

Lab Purpose:
     Solve some problems on activ physics on emission, absorption, and stimulation in relation to
     Lasers.

Part 1: Answer Questions

Question 1:

 Question 2:

 Question 3:

 
Question 4:

 The Answers:

     The answer to number 3 is confusing without context. The question was if the time atoms spent
     in their excited states was constant, however due to this being spontaneous emission of photons
     their can not be any set amount of time an atom spends in an excited state.

Lab 14: Color and Spectra

Lab Purpose:
     Examine the Spectrum of white light. More importantly compare between white light and the
     spectrum of single elements and explain why they are so radically different.

Part 1: White Light

     As can be seen in the picture, white light produces the full spectrum as a single line with multiple
     transitions.

     In our calculations, we obtained a range of 390 to 743 nanometers of wavelength which is very
     close to the 390 to 750 nanometer expected from white light.

Part 2: Mystery Element X

     This picture should strike people as odd, because the light given off by the mystery element
     does not produce a single line, but many distinctly colored "clones" of itself. However, being
     a student of physics, I have already learned that this is due to photon emission from elements
     being quantized, meaning only certain colors can be shown. Hooray education.

     In the picture above, the upright calculations show the different wavelengths that we have found
     compared to the expected wavelengths of Helium. There is a deviation of 18.2 nanometers.

Part 3: Hydrogen
     Sadly, a picture for the hydrogen spectrum could not be obtained, as the spectra was too dim to be
     seen. However, data was collected on 3 of the spectra lines that could be seen out of the 4 we
     expected.

     Correcting for error we get the equation lambda = 1.07 lambda_o - 8
     This error is quite large with a slope increase of 7%, however is could easily be attributed to
     the hydrogen tube being contaminated by other particles.

Lab 13: Activ Physics on Modern Physics

Lab Purpose:
     Do problems on time dilation to assist in complete understanding of the concept.

Part 1: Time Dilation

    
     These problems (work done manually by Austin Ku) were based on time dilation and asked some
     simple questions about the concepts of the dilation.

Part 2: Length Contraction

     These problems dealt with length contraction and many questions were similar in idea to those of
     the time dilation ones. The only interesting one was question 3, equivalent "length" objects must
     have equivalent relative velocities, but we can tell this is not true because one clock is moving
     where as the other is not.

Lab 12: CD Diffraction

Lab Purpose:
     Determine the size of the holes that are burned into the disc by examining the diffraction pattern
     that appears when a laser is shone on the recording side.

Part 1: Experiment

     This is a picture of our setup, the laser strikes the cd and bounces back slightly at an angle
     towards the laser. We then have a whiteboard placed right next to the point of emission and we
     measure the distance from the center and use that as our maxima distance.

     Calculations are quite trivial as it's mostly simple algebra. The value we obtained is
     1.5645 ± .0035 micrometer. The standard value is 1.6 micrometers, which means our value has
     an error of 2.2%.

Lab 11: Measuring a Human Hair

Lab Purpose:
     Using a human hair as a double slit, we attempt to find the width of the hair based upon the
     diffraction pattern that is shown.

Part 1: Experiment
     A hair was taped onto a card that had a hole punched into it.  This hole allows the laser to pass
     through while also interacting with the hair to cause a diffraction pattern as shown below.

    As we expected, the laser does cause a diffraction pattern.  We can use the difference between the
    maxima to determine the width of the hair.

     Our calculations produce a value of 97 ± 63 micrometers, putting it well within the expected
     values.  A significant portion of the error is due to the assumption that error in L is 2 cm.

Lab 10: Lenses

Lab Purpose:
     Observe changes in a real image when varying distance and amount of lens being covered.

Part 1: Focal Length
     To determine focal length, we went outside and used the sun as a source of parallel rays and then
     varied the distance until we found a distance that created the smallest spot.
     f = 18.3  ± .5 cm

     
     As you can see in the graph, we get obtain a slope of .928 and an x intercept of 5.067. The slope
     should be one, however we have an error of 7.2%. The inverse of the intercept should also be
     our focal length which is 19.7 cm. This is not within the bounds of uncertainty and is an error of
     7.8%.

Lab 9: Concave and Convex Mirrors

Lab Purpose:
      Examine and analyze the image that is formed by a convex and concave mirror.

Part 1: Convex Mirrors

      Images appear smaller and upright. The image appears to be further to the mirror than the actual
      object.  Moving the object closer increases the height of the image non linearly and for moving
      objects further from the mirror the image decreases in height non linearly.

Part 2: Concave Mirrors

      

     Images appear larger then object. Image is upright after coming close to the mirror and inverted

     from before that point.Compared to the object, the image seems to be closer to the mirror.  When

     you move the object closer to the mirror the image appears to slightly decrease in size. If you

     move the object significantly far away from the mirror, the image inverts.