Q1: Heat transfer co-efficient (h₁) for liquids increases with

ANS:A - increasing temperature.

When the temperature of a liquid increases, its molecules gain more thermal energy, causing them to move more vigorously. This increased molecular motion leads to higher rates of convection within the liquid. In the context of heat transfer, the heat transfer coefficient (h1) is a measure of how effectively heat is transferred from a hot surface to the fluid (liquid in this case). When the temperature of the liquid increases, the temperature gradient between the surface and the bulk fluid also increases. This larger temperature difference enhances the convective heat transfer process. Additionally, as the liquid temperature rises, its viscosity tends to decrease. A decrease in viscosity reduces flow resistance, allowing the liquid to flow more easily across the surface. This increased fluid motion further promotes convective heat transfer. Therefore, as the temperature of the liquid increases, both the thermal energy of the molecules and the convective motion of the fluid increase, leading to a higher heat transfer coefficient (h1).