Related Questions

A semicircular disc rests on a horizontal surface with its top flat surface horizontal and circular portion touching down. The coefficient of friction between semi circular disc and horizontal surface is µ. This disc is to be pulled by a horizontal force applied at one edge and it always remains horizontal. When the disc is about to start moving, its top horizontal force will
A Remain horizontal
B Slant up towards direction of pull
C Slant down towards direction of pull
D None of the above
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 identical situation, condensing film coefficient in case of a horizontal condenser is almost __________ the value expected in case of vertical condenser.
A Half
B Twice
C Thrice
D Five times
Vertical condenser is advantageous to the horizontal condenser from operation point of view, when
A Hydrostatic head is required for refluxing the condensate
B Only the function of condensation is to be carried out
C Sub cooling of condensate is desired
D Both the functions of condensation & sub cooling are carried out in a single unit
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
How are the efficiencies of any heat engine (miu) and reversible heat engine (miuR) compared, when both are operating between same heat source and same heat sink?
A miu = miuR
B miu>miuR
C miu
D none of these
The thermal efficiency of the engine with condenser as compared to without condenser, for a given pressure and temperature of steam, is
A Higher
B Lower
C Same as long as initial pressure and temperature is unchanged
D None of the above
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
The concept of overall coefficient of heat transfer is used in heat transfer problems of
A Conduction
B Convection
C Radiation
D Conduction and convection
The concept of overall coefficient of heat transfer is used in case of heat transfer by
A Conduction
B Convection
C Radiation
D Conduction and convection

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