Q1: With the increase of temperature, the Col-burn jH factor

ANS:A - increases.

The Colburn jH factor, also known as the heat transfer coefficient, generally increases with an increase in temperature. This phenomenon is typically observed in many heat transfer processes, especially in forced convection and natural convection. As the temperature increases, the thermal energy of the fluid also increases, leading to more vigorous molecular motion and enhanced convective heat transfer. Consequently, the heat transfer coefficient tends to increase with temperature. Therefore, the correct statement is: "increases."