ABSTRACT

Transfer of energy by radiation is significantly different from other energy transfer phenomena because it is not proportional to a temperature gradient and does not need a natural medium to propagate. Typically, any molecule possesses translation, vibrational, rotational, and electronic energy under quantum states. Passing from one energy level to another implies energy absorption or emission by a molecule. On the other hand, a molecule emits energy as radiation when passing to a lower energy level. The absorption or emission of energy is in the form of photons that have a double nature: particle-wave. Any body at a temperature higher than absolute zero

2.1 Introduction .................................................................................................... 19 2.2 Characteristics of Thermal Radiation.............................................................20