Dear student,When a collection of molecules absorbs thermal energy, it increases their average kinetic energies, and thus their temperature. All molecules will possess translational kinetic energy at all temperatures above absolute zero. In other words, the higher the temperature, the faster they move...(2) Black-body radiation has a characteristic, continuous frequency spectrum that depends only on the body's temperature, called the Planck spectrum or Planck's law. As the temperature increases past about 500 degrees Celsius, black bodies start to emit significant amounts of visible light.Regards.