Top 1000+ Solved Heat Transfer (HT) MCQ Questions Answer
Q. The actual temperature drop across the heating surface in an evaporator depends on the
a. Feed
b. Depth of liquid over heating surface
c. Pressure difference between steam chest and vapour space
d. All (A), (B) and (C)
Q. A diathermanous substance __________ the thermal radiation completely.
a. Absorbs
b. Reflects
c. Transmits
d. None of these
Q. 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
Q. Boiling point elevation of a solution of NaOH
a. Increases rapidly with temperature rise
b. Is almost independent of temperature
c. Is almost independent of pressure
d. Both (B) and (C)
Q. Thermal conductivity of a conducting solid material depends upon its
a. Temperature
b. Porosity
c. Both (A) & (B)
d. Neither (A) nor (B)
Q. Pick out the wrong statement.
a. Reciprocal of the resistance to heat flow is called thermal conductance
b. Unit of thermal conductance is W/°K
c. Thermal conductance of a wall of thickness 'L', thermal conductivity 'k' and heat flow area 'A' is kL/A
d. None of these
Q. Overall thermal resistance for conductive heat transfer through a series of flat resistancesis equal to the
a. Maximum resistance in the series
b. Sum of all resistances
c. Average of all resistances
d. Minimum resistance presents in the series
Q. When vaporisation takes place directly at the heating surface, it is called
a. Film boiling
b. Nucleate boiling
c. Vapour binding
d. None of these
Q. Arithmetic mean area can be used in heat transfer problem to calculate the heat flow by conduction through a cylinder which is
a. Thin walled having the value of Ao Ai /< 2
b. Thick walled
c. Having the value of Ao/Ai > 2
d. Both (B) and (C)
Q. The concept of overall coefficient of heat transfer is used in heat transferproblems of
a. conduction
b. convection
c. radiation
d. all the three combined
e. conduction and comte_ction.
Q. In heat transfer, conductance equals conductivity (kcal/hr/sqm/°C/cm) dividedby
a. hr (time)
b. sqm (area)
c. °C (temperature)
d. cm (thickness)
e. kcal (heat).
Q. The amount of heat flow through a body by conduction is
a. directly proportional to the surface area of the body
b. directly proportional to the temperature difference on the two faces of the body
c. dependent upon the material of the body
d. inversely proportional to the thickness of the body
e. all of the abov
Q. Which of the following has least value of conductivity
a. glass
b. water
c. plastic
d. rubber
e. air.
Q. Which of the following is expected to have highest thermal conductivity
a. steam
b. solid ice
c. melting ice
d. water
e. boiling water.