Why do we perform stork stand test

umm  becuase it is a test and you need them

Explanation:

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.

electric field is a function of 1/r^2

yes, the force per unit charge for a point charge is inverse square law.