Describe how to magnetise a steel using a direct current (d. c) and
a coil.

A bar of steel can be magnetised by placing it in a coil of wire (solenoid). Passing a d.c. (direct current) through the wire will magnetise the bar.

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.