Top 1000+ Solved Heat Transfer (HT) MCQ Questions Answer
Q. Thermal conductivity of glass-wool varies from sample to sample because ofvariation in
a. composition
b. density
c. porosity
d. structure
e. all of the abov
Q. Thermal conductivity of a material may be defined as the
a. quantity of heat flowing in one second through one cm cube of material when opposite faces ^re maintained at a temperature difference of 1°C
b. quantity of heat flowing in one second through a slab of the material of area one cm square, thickness 1 cm when its faces differ in temperature by 1°C
c. heat conducted in unit time across unit area through unit thickness when a temperature difference of unity is maintained between opposite faces
d. all of the above
e. none of the abov
Q. Which of the following has maximum value of thermal conductivity
a. aluminium
b. steel
c. brass
d. copper
e. lead.
Q. Moisture would find its way into insulation by vapour pressure unless it isprevented by
a. high thickness of insulation
b. high vapour pressure
c. less thermal conductivity insulator
d. a vapour seal
e. all of the abov
Q. Heat is transferred by all three modes of transfer, viz, conduction, convectionand radiation in
a. electric heater
b. steam condenser
c. melting of ice
d. refrigerator condenser coils
e. boiler.
Q. According to Prevost theory of heat exchange
a. it is impossible to transfer heat from low temperature source to t high temperature source
b. heat transfer by radiation requires no medium
c. all bodies above absolute zero emit radiation
d. heat transfer in most of the cases takes place by combination of conduction, convection and radiation
e. rate of heat transfer depends on thermal conductivity and temperature differenc
Q. The ratio of heat flow Q1/Q2 from two walls of same thickness having their thermal conductivities as ATj – 2K2 will be
a. I
b. 0.5
c. 2
d. 0.25
e. 4.0
Q. Heat transfer by radiation mainly depends upon
a. its temperature
b. nature of the body
c. kind and extent of its surface
d. all of the above
e. none of the abov
Q. Thermal diffusivity is
a. a dimensionless parameter
b. function of temperature
c. used as mathematical model
d. a physical property of the material
e. useful in case of heat transfer by radiation.
Q. Thermal diffusivity of a substance is .
a. proportional of thermal conductivity
b. inversely proportional to k
c. proportional to (k)
d. inversely proportional to k2
e. none of the abov
Q. Thermal conductivity of wood depends on
a. moisture
b. density
c. temperature
d. all of the above
e. none of the abov
Q. In convection heat transfer from hot flue gases to water tube, even though flow may be turbulent, a laminar flow region (boundary layer of film) exists close to the tube. The heat transfer through this film takes place by
a. convection
b. radiation
c. conduction
d. both convection and conduction
e. none of the abov
Q. Film coefficient is defined as Inside diameter of tube
a. Equivalent thickness of film
b. Thermal conductivity Equivalent thickness of film Specific heat x Viscocity
c. Thermal conductivity Molecular diffusivity of momentum Thermal diffusivity
d. Film coefficient x Inside diameter Thermalconductivity
e. none of the abov
Q. Heat conducted througfi unit area and unit thick face per unit time whentemperature difference between opposite faces is unity,is called
a. thermal resistance
b. thermal coefficient
c. temperature gradient
d. thermal conductivity
e. heat-transfer.