The class is about Electricity and Magnetism. The website wants exactly the perfect answer and in the same metric system units that are stated on the calculators that are on the picture for the question, if not, it'll mark it wrong.

321 13 I'I'ODIEITI .1 Homemade Solenoid A 22.6-m-long copper wire, 2.19 mm in diameter including insulation, is tightly wrapped in a single layer with adjacent coils touching, to form a solenoid of diameter 2.36 cm. What is a. the length L of the solenoid, and b. the magnetic eld at the center when the current in the wire is 18.9 A? 'See Section 28-5 for a discussion of solenoids