Question 321. A designer chooses the values of fluid flow rates and specific heats in such a manner that the heat capacities of the two fluids are equal. A hot fluid enters the counter flow heat exchanger at 100°C and leaves at 60°C. A cold fluid enters the heat exchanger at 40°C. The mean temperature difference between the two fluids is

Question 322. In a shell and tube heat exchanger, baffles are provided on the shell side to

Question 323. The process of heat transfer from one particle of the body to another by the actual motion of the heated particles, is called

Question 324. According to Newton's law of cooling, the heat transfer from a hot body to a cold body is

Question 325. Absorptivity of a body will be equal to its emissivity

Question 326. In a heat exchanger with one fluid evaporating or condensing, the surface area required is least in

Question 327. Fourier's law of heat conduction is valid for

Question 328. A steam pipe is to be lined with two layers of insulating materials of different thermal conductivities. For the minimum heat transfer,

Question 329. Upto the critical radius of insulation,

Question 330. Fourier's law of heat conduction is (where Q = Amount of heat flow through the body in unit time, A = Surface area of heat flow, taken at right angles to the direction of heat flow, dT = Temperature difference on the two faces of the body, dx = Thickness of the body, through which the heat flows, taken along the direction of heat flow, and k = Thermal conductivity of the body)