Primary and secondary waves are
waves, and love waves are
waves
surface, body
body, surface
slow, fast
slow, body

adding a(n) to an electric circuit would increase the magnetic field around a wire;

b. solenoid

a solenoid is a type of electromagnet whose purpose is to generate a controlled magnetic field.

if the purpose of the solenoid is instead to impede changes in the electric current, a solenoid can be more specifically classified as an inductor rather than an electromagnet.

grav force prop 1/r squared 2r all squared is 4rsquared 1/4rsquared quartered