Related Questions

Extended heat transfer surface like fins are used to increase the heat transfer rate. Fin efficiency is defined as the ratio of heat transferred across the fin surface to the theoretical heat transfer across an equal area held at the
A Surrounding temperature
B Average temperature of the fin
C Temperature of the fin end
D Constant temperature equal to that of the base
The scales form in heat exchanges after a period of operation and provide additional resistance to heat transfer with some heat transfer coefficient . The reciprocal of this scale heat transfer coefficient is called .
A scaling factor
B forming factor
C resisting factor
D fouling factor
For shell and tube heat exchanger, with increasing heat transfer area, the purchased cost per unit heat transfer area
A Increases
B Decreases
C Remains constant
D Passes through a maxima
Heat conducted through per unit area and unit thick face per unit time when temperature difference between opposite faces is unity, is called
A Thermal resistance
B Thermal coefficient
C Temperature gradient
D Thermal conductivity
Heat flux increases with temperature drop beyond the Leiden frost point in the plot of heat flux vs. temperature drop for a boiling liquid, because
A Convection becomes important
B Conduction becomes important
C Radiation becomes important
D Sub-cooled boiling occurs
per day wage rate of workers is reduced 50% due to economic slowdown. After one year, the wage rate is increased by 60% . If the per day wage rate before the decrease was Tk. 100, then what is the per day wage rate now?
A 90
B 100
C 60
D 80
per day wage rate of workers is reduced 50% due to economic slow down. After one year ,the wage rate is increased by 60% . If the per day wage rate before the decrease was Tk.. 100, then what is the per da y wage rate Now?
A 90
B 100
C 60
D 80
Per day wage rate of workers is reduced 50% due to economic slowdown. After one year, the wage rate is increased by 60%. If the per day wage rate before the decrease was Tk 100, then what is the per day wage rate now?
A 90
B 100
C 60
D 80
In case of heat transfer by conduction in a hollow cylinder, __________ mean area is used to calculate the heat transfer rate.
A Geometric
B Arithmetic
C Logarithmic
D Either A, B or C
For turbulent flow in a tube, the heat transfer co-efficient is obtained from the Dittus-Boelter correlation. If the tube diameter is halved and the flow rate is doubled, then the heat transfer co-efficient will change by a factor of
A 1
B 1.74
C 6.1
D 37

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