This is an open book examination. You may use any available references or notes but do not consult other students or staff members for help. The completed examination is to be returned not later than noon on Thursday, December 12.
1. Using simple lens theory, make a sketch to scale of a conventional compound microscope showing the several lenses and of the position, size and sense of the several images as related to the object. Use the case of an 8 mm. objective of 0.30 numerical aperature properly illuminated to use that full field and an ocular of 5X rating used with a tube length of 160 mm. The objective operates in air without an immersion fluid. Calculate the size of the virtual image seen with this system when used by direct vision, the size of image that would be cast on a screen 2 meters away from the ocular and the depth of focus to be expected with the above microscope when viewing an object 1/2 mm. in linear dimension. Always assume the system to be adjusted for sharp focus in the usual manner.
2. Identify six individuals who have made important contributions to biophysical science in the general area of acoustics or audition and make a brief but specific report on a contribution from each. Select your subjects so that they represent reasonably well the work of early biophysicists (say before 1920), recent work (since 1950) and that in between. Try to avoid overemphasis on any one topic and include at least one piece of work in which ultrasonics is involved. Give the key reference or references on which your resume is based in each case.
3. The following pairs of measurements of the diameter and thickness of a frog eye lens were made by the 16 members of a previous biophysics class. Using these data, estimate the best values for the diameter and thickness that you can deduce and associate with each a measure of the reliability of your estimate. This estimate should take the form of a value for the standard errors and of the standard deviations or of the corresponding two kinds of probable errors. If you are able, make the necessary calculations to determine whether students individually tended to make both readings high or low, i.e. whether the pairs of individual readings are correlated.
Diameter Thickness
4.15 mm. 3.73 mm.
4.l6 3.59
4.28 3.46
4.30 3.55
4.51 3.48
4.47 3.75
4.50 3.78
4.60 3.75
4.54 3.58
4.40 3.06
4.10 2.88
4.09 3.55
4.55 3.04
4.600 3.79
6.0 3.9200
4.650 4.050