Heat and Mass Transfer The thermal diffusivities for solids are generally More or less same as for liquids and gases Less than those for liquids Less than those for gases More than those for liquids and gases More or less same as for liquids and gases Less than those for liquids Less than those for gases More than those for liquids and gases ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer 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 20°C 60°C 40°C 66.7°C 20°C 60°C 40°C 66.7°C ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer An electric cable of aluminium conductor (k = 240 W/mK) is to be insulated with rubber (k = 0.15 W/mK). The cable is to be located in air (h = 6 W/m²). The critical thickness of insulation will be 800 mm 40 mm 160 mm 25 mm 800 mm 40 mm 160 mm 25 mm ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer In heat transfer, conductance equals conductivity (kcal/hr/sq.m/°C/cm) divided by °C (temperature) Sq. m (area) Hr (time) K.cal (heat) °C (temperature) Sq. m (area) Hr (time) K.cal (heat) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Radiation is the process of heat transfer in which heat flows from a ________, in a straight line, without affecting the intervening medium. Hot body to cold body Larger body to smaller body Smaller body to larger body Cold body to hot body Hot body to cold body Larger body to smaller body Smaller body to larger body Cold body to hot body ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Two balls of same material and finish have their diameters in the ratio of 2: 1 and both are heated to same temperature and allowed to cool by radiation. Rate of cooling by big ball as compared to smaller one will be in the ratio of 0.043055555555556 0.16736111111111 0.084027777777778 0.042361111111111 0.043055555555556 0.16736111111111 0.084027777777778 0.042361111111111 ANSWER DOWNLOAD EXAMIANS APP