Top 1000+ Solved Heat Transfer (HT) MCQ Questions Answer
Q. Four rods with different radii 'r' and length 'l' are used to connect to reservoirs of heat at different temperature. Which one of them with conduct most heat?
a. r = 1 cm, l = 1m
b. r = 2 cm, l =
c. r = 2 cm, l = 2m
d. r =
e. 37,500 kg
Q. Which type of heat exchanger an automobile radiator is?
a. Recuperator type
b. Counter flow type
c. Cross flow type
d. Regenerator type
e. Parallel flow type
Q. The wavelength for maximum emissive power is given by
a. Stefan Boltzman's law
b. Wein's law
c. Fourier's law
d. Kirchhoff's law
e. Planck's law
Q. The emissivity of a body will be equal to absorptivity when
a. Body is in thermal equilibrium
b. Temperature of body is rising
c. Temperature of body is falling
d. Body is at low temperature
e. Body is at high temperature
Q. In constant volume Hydrogen gas Thermometer, a correction has to be applied, because
a. Hydrogen is impure
b. Expansion of Hydrogen is non-linear
c. Density of mercury changes
d. None of the above
e. Optical pyrometer
Q. All substances emit radiation, the quality and quantity depending upon the absolute temperature and the properties of the material composing the radiating body. The above statement is known as the statement of
a. Stefan-Bolzmann's law
b. Kirchhoff's law
c. Planck's law
d. D Alambert's rule
e. Law of radiation
Q. The unit of thermal conductivity in M.K.S. unit is
a. kcal/m/?C
b. kcal/m/sec?C
c. kcal/m2/?C sec
d. None of the above
e. Nichrome
Q. Radiation heats transfer between two surfaces can be reduced by
a. Preheating the surfaces closer together
b. Introducing radiation shield between the surfaces
c. Polishing the surface
d. 37,500 kg
e. Bringing the surfaces closer together
Q. Thermal diffusivity is
a. A function of temperature
b. A mathematical formula only
c. A dimensionless parameter
d. A configuration for heat conduction
e. A physical property of the material
Q. In a thermal power plant, cooling towers are used to cool
a. steam
b. condensed wate
c. circulating
d. All of the above
e. 37,500 kg
Q. A steam pipe is to be insulated by two insulating materials put over each other. For best results
a. Better matt. Over pipe and inferior over it
b. Inferior matt. Over pipe and better over it
c. Can be in any order
d. None of the above
e. Nichrome
Q. The rate of heat flow from a 50 mm thick wall of material having thermal conductivity of 40 W/m?C for a temperature difference of 10?C will be
a. 800 W/m2 - hr
b. 200 W/m2 - hr
c. 2000 W/m2 - hr
d. 80 W/m2 - hr
e. 8000 W/m2 - hr
Q. All temperatures above the freezing point of gold are usually determined by
a. Thermo couple
b. Gas thermometer
c. Optical pyrometer
d. Resistance bridge
e. Any of the above
Q. Two large closely spaced concentric spheres (both of which are perfect black body radiators) are maintained at temperatures of 127?C and 27?C respectively. The space in between the two spheres is evacuated. Taking Stefan Boltzmann constant as 5.67 x 108 watt m2K the rate of radiation in watts per sq. m between the two spheres is approximately
a. 992
b. 762
c. 37,500 kg
d. 852
e. 666
Q. A body cools from 90?C to 80?C in 5 minutes. Under the same external conditions to cool from 80?C to 70?C the body will take
a. 2.5 minutes
b. Cannot be predicted
c. 5 minutes
d. More than 5 minutes
e. 4 minutes