Air enters a 12 m long, 7 cm diameter pipe at 50oC at a rate of 0.06 kg/s. The air is cooled at an average rate of 400W per m2 surface area of the pipe. What is the exit temperature

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.