Radiation that is redshifted has the peaks of its waves with a. more energy
b. farther apart
c. closer together
d. both closer together and with more energy

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