Q1: For a perfectly transparent surface (like gases), the

ANS:B - transmissivity = 1

Transmissivity refers to the ability of a material or surface to allow radiation to pass through it. When the transmissivity of a surface is equal to 1, it means that all incident radiation is able to pass through the surface without being absorbed or reflected. In other words, the material is perfectly transparent to the radiation. For example, in the case of gases such as air or certain types of clear glass, the molecules are spaced far enough apart that incident radiation encounters minimal obstruction. As a result, almost all of the radiation passes through the material, making it highly transparent. Transmissivity is particularly relevant in fields such as optics and heat transfer, where the ability of materials to transmit light or heat is of interest. When transmissivity is equal to 1, it indicates a complete absence of absorption or reflection, and all incident radiation is transmitted through the material without any loss of intensity or energy.