What is domain theory? how does it explain how an electromagnet become magnetic

What is a carrier wave and how does it affect what you hear on the radio

Aprotein molecule in an electrophoresis gel has a negative charge.the exact charge depends on the ph of the solution, but 30 excesselectrons is typical. what is the magnitude of the electric forceon a protein with this charge in a 1500 n/c electric field?

The basketball coach tells his team to run sprints back and forth across the court, which is 30 m long. they start at the left end of the court, run back and forth 6 times, then end back at the left end of the court where they began. what distance did they run? what is their displacement?