A. Power density
B. Temperature difference between heated surface and coolant
C. Thermal resistivity, density, specific heat
D. Gravitational constant
E. All of the above
Related Mcqs:
- The heat dissipated by from a surface depends upon its temperature and its characteristics like colour, roughness etc?
A. conduction
B. convection
C. radiation
D. any of the above - The heated parts of an electrical machine dissipate heat into their surroundings by which of the following modes of heat dissipation ?
A. Conduction
B. Convection
C. Radiation
D. All of the above - The value of exciting or magnetizing current depends upon which of the following factors ?
A. Total m.m.f. required
B. The number of turns in the exciting winding
C. The way in which the winding is distributed
D. All of the above - In _________ machines, the size of the shaft is decided by the critical speed which depends on the deflection of the shaft?
A. small
B. medium
C. large
D. any of the above. - The heat dissipating capability of transformers of ratings higher than 30 kVA in increased by providing which of the following ?
A. Corrugations
B. Fins
C. Tubes
D. Radiator tanks
E. All of the above - The mcrease in heat dissipation by air blasts is due to increase in______________?
A. conduction
B. convection
E. radiation
D. any ofthe above - Hydrogen has a heat transfer co-efficient __________ times that of air?
A. 1.5
B. 2.5
C. 3.5
D. 4.5 - The change in flux linkages can be caused in which of the following ways ?
A. The flux is constant with respect to time and is stationary and the coil moves through it
B. The coil is stationary with respect to flux and the flux varies in magnitude with respect to time
C. Both the changes mentioned above occur together, i.e., the coil moves through a time varying field
D. All of the above - Which of the following methods is used for air cooling of turbo-alternators ?
A. One sided axial ventilation
B. Two sided axial ventilation
C. Multiple inlet system
D. All of the above - The design of electromagnets is based upon which of the following fundamental equations ?
A. Force equation
B. Magnetic circuit equation
C. Heating equation
D. Voltage equation
E. All of the above
