Miscellaneous

Sample questions

  1. Why do the diameters of bones across species scale with their lengths to the 3/2 power?
  2. A ventilation system steadily blows air at temperature 18 °C into a room.
    1. If there are enough people in the room to raise the temperature to a steady-state value of 24 °C, by what fraction is the air leaving the room depleted in oxygen?
    2. On what timescale should the vents completely replace the air, to prevent the temperature from rising above 24 °C?
  3. Knowing that the angular resolution of the human eye at the center of its field of view (fovea) is diffraction-limited, estimate the surface density (number per unit area) of light-sensitive cells (cones) at the fovea. For reference, pupil sizes range from 0.2 to 0.4 cm. Estimate also the pixel sizes of TVs.