where B is the direction (B=0.7G) and R is the radius,
I=2*7*10^(-5) x 0.1/4pi*1-^(-7) Ampers
the answer is c.)
adding a(n) to an electric circuit would increase the magnetic field around a wire;
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.