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
A _________ in a boiler is used to put off fire in the furnace of the boiler when the level of water in the boiler falls to an unsafe limit.
A Blow off cock
B Fusible plug
C Stop valve
D Safety valve
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
The predominant mode of heat transfer which takes place from boiler furnace to water walls of a boiler is
A Conduction
B Convection
C Both A & B
D Radiation
A garments factory employs 3 categories of workers K, M and N. The efficiency of the 3 categories of workers to do a specific task is in the ratio of 3 : 5 : 6 respectively and the factory employs 15 of category K, 12 of category M and 3 of category N. If the total wages paid to the entire group of 30 workers is Tk. 492 per hour, what will be the wages earned by a category N worker for an 8-hour day?
A Tk. 144
B Tk. 72
C Tk. 192
D Tk. 576
Q.(1-4): Answer the questions on the basis of the information given below. * F,G and H are insurance companies , Q,R,S and T are private detectives .Each detective works for at least one of the insurance companies. * Q always works for F and at least one of the other companies. Some of the time G employs only one of these detectives,' the rest of the time it employs exactly two of them. *F and H each employ exactly two of these detectives all the time. If R works for H only, and if S works for G and H only, T works for--
A F only
B G only
C H only
D both F and G
The delivery pressure of boiler feed water pump compared to the boiler steam pressure is
A Same
B Slightly less
C Slightly more
D Much more
If a heat transfer surface is pock-marked with a number of cavities, then as compared to a smooth surface the heat transfer by __________ will not increase.
A Convection
B Nucleate boiling
C Radiation
D Conduction
Heat transfer to the water wall in a high pressure water wall type boiler furnace is mainly by
A Conduction
B Convection
C Both A & B
D Radiation

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