9.7/3.33 round answer to the correct number of significant digits

2.9

Explanation:

9.7 / 3.33 = 2.912912912...

We need to round to the correct number of significant figures.  9.7 has two significant figures, and 3.33 has three significant figures.  We need to round to the least number of significant figures available, so we round to two.

2.91 ≈ 2.9

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.