Q1: Pick out the wrong statement about nucleate boiling.

ANS:D - The temperature is less than that of film boiling.

The statement "The temperature is less than that of film boiling" refers to the fact that in nucleate boiling, the temperature of the heated surface is generally lower than in film boiling. In nucleate boiling, bubbles of vapor form directly on the heated surface due to localized superheating of the liquid near surface irregularities or nucleation sites. The bubbles then detach from the surface and rise through the liquid, carrying away heat in the process. However, as the bubbles form and rise, they also create a thin vapor layer around the heated surface. This vapor layer acts as an insulator, reducing the direct contact between the liquid and the heated surface. In contrast, in film boiling, a continuous vapor film forms between the heated surface and the bulk liquid. This vapor film effectively insulates the surface, preventing direct contact between the liquid and the surface. As a result, the temperature of the heated surface in film boiling can be much higher than in nucleate boiling because the liquid is not in direct contact with the surface. Therefore, in nucleate boiling, the temperature of the heated surface is generally lower compared to film boiling due to the absence of a continuous vapor film insulating the surface and allowing direct contact between the liquid and the surface.