2005 Nobel Prize in Physics, John Hall, JILA/Physics, University of Colorado

1
2005 Nobel Prize in Physics, John Hall,
JILA/Physics, University of Colorado
for his contributions to the development of
laser-based precision spectroscopy, including the
optical frequency comb technique. Measurement
precision to 1 part in 1015!
2
(D) None of these.
3

• In a distant foreign country, the distribution of
  heights of adult males is found to be gaussian
  with a mean of 510 and a standard deviation of
  3. What fraction of the males is taller than
  64?
• less than 1
• about 2.5
• (C) about 5
• (D) about 15
• (E) none of these

4
Data points (with error bars) and theory y m x
b are plotted on the same graph
What can you conclude about the uncertainties
shown? A) These are 1-sigma error bars B) These
are 2-sigma error bars C) Something is
definitely wrong the error bars are too small
because they dont all agree with theory Answer
These are 1-sigma error bars There is a 32
chance that any one measurement will fall outside
the mean ? 1-sigma window
5
A series of N measurements of a quantity is
taken with apparatus A. The distribution of A
results is shown. Apparatus A is replaced with
apparatus B, and a new series of N/4 measurements
of the same quantity is taken. The B results are
shown.
Which series of measurements has the smaller
standard deviation s? A) A B) B C) both A and
B have the same standard deviation D) impossible
to tell from the information given Answer B
The B distribution has a width which is about ½
of that of A.
6
A series of N measurements of a quantity is
taken with apparatus A. The distribution of A
results is shown. Apparatus A is replaced with
apparatus B, and a new series of N/4 measurements
of the same quantity is taken. The B results are
shown. The standard deviation of A is twice that
of B.

• From which set of measurements can you make the
  best estimate of the average value of x?
• A
• B
• It is about equal.
• D) impossible to tell without more detailed
  information

The error in the average is smean s/SQRT(N)