### Category: Mechanical Engineering

Latest multiple choice questions with answers for mechanical engineering students.

## Mechanical Engineering MCQs [Quiz 37]

Q1. Which of the following has maximum value of thermal conductivity
(a) aluminium
(b) steel
(c) brass
(d) copper

Q2. Moisture would find its way into insulation by vapour pressure unless it is prevented by
(a) high thickness of insulation
(b) high vapour pressure
(c) less thermal conductivity insulator
(d) a vapour seal
(e) all of the above.

Q3. Heat is transferred by all three modes of transfer, viz, conduction, convection and radiation in
(a) electric heater
(b) steam condenser
(c) melting of ice
(d) refrigerator condenser coils
(e) boiler

Q4. 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 difference.

Q5. 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

Q6. 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 above.

Q7. 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.

Q8. 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 above.

Q9. Unit of thermal diffusivity is
(a) m2/hr
(b) m2/hr°C
(c) kcal/m2 hr
(d) kcal/m.hr°C
(e) kcal/m2 hr°C

Q10. Thermal conductivity of wood depends on
(a) moisture
(b) density
(c) temperature
(d) all of the above
(e) none of the above.

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