Heat Transfer MCQs

Asymptotic conditions is reached, when for a fluid flowing in laminar flow through a long tube

Which of the following has the minimum thermal conductivity?

A long iron rod initially at a temperature of 20°C has one end dipped in boiling water (100°C) at time, t = 0. The curved surface of the rod is insulated so that heat conduction is one dimensional in the axial direction. The temperature at a distance 100 mm from the dipped end becomes 40°C at time, t = 200 s. The same temperature is achieved at a distance of 200 mm from the dipped end at time

Fresh orange juice contains 12% (by weight) solids and the rest water 90% of the fresh juice is sent to an evaporator to remove water and subsequently mixed with the remaining 10% of fresh juice. The resultant product contains 40% solids. The kg of water removed from 1 kg fresh juice is

In case of a supercooled solution, which is on the verge of crystallisation, the free energy of the solution as compared to that of the solid is

Heat transfer occurs by natural convection because change in temperature causes difference in

In a parallel flow heat exchanger, if the outlet temperature of hot and cold fluids are the same, then the log mean temperature difference (LMTD) is

The capacity of double-effect evaporator is less than half of the capacity of two single effects, each of which is operating over same terminal temperature difference, when the

Choose the most important factor on which the heat conducted through a wall in a unit time will depend on?