Select the correct answer. Which of these is described as force per unit charge on a positive test charge?

А. test charge

B. source charge

C. electric force

D. electric field

E. electric current

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