3. Atmospheric pressure is often given in units of millimeters of mercury. This refers to the height of a mercury column above the mercury's surface at the base of a barometer . The force exerted by the atmosphere on the surface of the mercury in the reservoir equals the weight of the mercury in the column . If the mercury column extends 760 mm above the mercury's surface in the reservoir , what is the atmosphere's pressure over the mercury ? Use 13.6*10^ 3 kg/m^ 3 for the density of mercury

Certain bacteria (such as aquaspirillum magnetotacticum) tend to swim toward the earth’s geographic north pole because they contain tiny particles, called magnetosomes, that are sensitive to a magnetic field. if a transmission line carrying 100 a is laid underwater, at what range of distances would the magnetic field from this line be great enough to interfere with the migration of these bacteria? (assume that a field less than 5% of the earth’s field would have little effect on the bacteria. take the earth’s field to be 5.0 * 10-5 t, and ignore the effects of the seawater.)