The orbital radius of the Earth (the average Earth-Sun distance) is 1.496 × 1011 m. Mercury’s orbital radius is 5.79 × 1010 m and Pluto’s is 5.91 × 1012 m. Calculate the time required for light to travel from the Sun to each of the three celestial bodies

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.)