Well pollution will most likely go down since people won't be driving in there own cars<span />
To solve this problem we will use the Ampere-Maxwell law, which describes the magnetic fields that result from a transmitter wire or loop in electromagnetic surveys. According to Ampere-Maxwell law:

Where,
B= Magnetic Field
l = length
= Vacuum permeability
= Vacuum permittivity
Since the change in length (dl) by which the magnetic field moves is equivalent to the perimeter of the circumference and that the electric flow is the rate of change of the electric field by the area, we have to

Recall that the speed of light is equivalent to

Then replacing,


Our values are given as




Replacing we have,



Therefore the magnetic field around this circular area is 
Wavelength = (speed)/(frequency) = 300,000,000/120,000,000 = 2.5 meters
Yes. That's a true statement. Ultrasound is indeed the name given to sounds with frequencies above the human range of hearing.
Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans can't hear it.