1. Mirror #1 Mirror #1 Mirror #2 Mirror #2 Volts Volts t>t1 t<t1
Problem 3 (50 Marks) THIS IS AN OLD EXAM QUESTION
You and your lab partner Billy-Bob are using the interferometer below to measure the acceleration of gravity (g). Mirror #1 is held fixed and mirror #2 is dropped at t=t1 and the scope records the output of detector. The entire interferometer is located in a vacuum chamber to minimize any effects of air.
t>t1
t<t1
Detector
Detector
Scope
Scope
Laser l
Laser l
Mirror #1
Mirror #1
Mirror #2
Mirror #2
a) Billy-Bob produces these two plots. Only one of these two scope traces shown below is correct. Pick the correct one, circle it, justify your selection
Volts
t-t1 (ms)
Volts
t-t1 (ms)
b) Now use data from the correct scope trace to calculate a value of g
c) Aside from any mechanical stability improvements, name at least two experimental procedures and/or changes one could do to improve the accuracy of your measurement of g using such an interferometer.
d) If the experiment was performed in air and the mirror was dropped a far enough distance, the resulting scope trace would be fundamentally different than the correct one shown in part a. Qualitatively sketch and describe this difference.
Note that this type of device is actually used to measure g, see Fig. 7 of paper linked on course webpage
Link repeated here: