Changing the of the flow of electric current in a wire coil reverses an electromagnet's north and south poles.
A charge
B type
C direction
D shape

Which of the following best describes internal energy? a. the difference between the kinetic and potential energies of the particles in a system b. the sum of the kinetic and potential energies of the particles in a system c. the sum of the kinetic and thermal energies of the particles in a system d. the difference between the kinetic and thermal energies of the particles in a system