Two charges, qA and qB, are separated by a distance, r, and exert a force, F, on each other. What new force will exist for the following scenario? Your answer should be given in multiples of F (i. e. 2F, ½F, etc.)

qA is doubled and r is doubled

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.)