What is a resistance training method that involves performing a set with light load followed by increasing the load and decreasing the repetitions with each continuing set?

Pyramid system

Explanation:

A pyramid system resistance training is a collection of sets of the same exercise, that start with light weights and higher repetitions, building up to heavier weights and fewer repetitions.

A full pyramid training is an extension of the above mentioned statement, reducing the weight after you have reached the peak until you complete the pyramid.

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.