When light and heat are not absorbed by an object, they are typically subjected to one of three processes: reflection, transmission, or scattering.
Reflection: When light or heat encounters a surface that is reflective, such as a mirror or a shiny metal, a significant portion of the energy is reflected back, bouncing off the surface. The angle at which the light or heat is reflected follows the law of reflection, which states that the angle of incidence (the incoming angle) is equal to the angle of reflection (the outgoing angle). Reflection allows us to see objects by reflecting light into our eyes and helps to maintain the energy balance of the object by preventing excessive heat absorption.
Transmission: When light or heat encounters a transparent or translucent material, such as glass or air, it can pass through the object, a process called transmission. The degree of transmission depends on the material's transparency and the wavelength of the light. Some materials allow certain wavelengths to pass through while absorbing or reflecting others. For example, glass allows visible light to transmit through while absorbing a minimal amount of heat. In the case of heat, materials like air are relatively transparent, allowing heat to pass through without significant absorption.
Scattering: Scattering occurs when light or heat encounters small particles or irregularities in the medium through which it travels. The incoming light or heat is redirected in different directions, resulting in a scattered pattern. This phenomenon is responsible for the blue color of the sky, as the shorter wavelengths of blue light are scattered more than longer wavelengths, such as red. Scattering can occur in various materials and mediums, including gases, liquids, and solids.
It's important to note that when light or heat is not absorbed by an object, it does not contribute to increasing the internal energy of the object. Instead, it is either reflected, transmitted, or scattered, depending on the nature of the object and the properties of the light or heat.