Are you guys looking for Mechanical Engineering MCQ Questions with Answers PDF Free Download as per Mechanical Engineering new exam pattern? You came to the right page. This may assist you to understand and check your knowledge about the Subjects. Students also can take a free test of the Multiple Choice Questions of Mechanical Engineering. Each question has four options followed by the right answer. These Mechanical Engineering MCQ Questions are selected supported by the newest exam pattern.
Q1. Wien’s law states that the wave length corresponding to __ is proportional to the absolute temperature.
(A) Minimum energy
(B) Maximum energy
(C) Both (A) and (B)
(D) None of these
Answer: (B) Maximum energy
Q2. When heat is transferred by molecular collision, it is referred to as heat transfer by
(A) Conduction
(B) Convection
(C) Radiation
(D) Scattering
Answer: (B) Convection
Q3. Thermal conductivity of wood depends on
(A) Moisture
(B) Density
(C) Temperature
(D) All of the above
Answer: (D) All of the above
Q4. The thermal diffusivities for gases are generally
(A) More than those for liquids
(B) Less than those for liquids
(C) More than those for solids
(D) Dependent on the viscosity
Answer: (A) More than those for liquids
Q5. Thermal conductivity of solid metals with rise in temperature normally
(A) Increases
(B) Decreases
(C) Remain constant
(D) May increase or decrease depending on temperature
Answer: (B) Decreases
Q6. Heat is closely related with
(A) Liquids
(B) Energy
(C) Temperature
(D) Entropy
Answer: (C) Temperature
Q7. The time constant of a thermocouple is
(A) The time taken to attain the final temperature to be measured
(B) The time taken to attain 50% of the value of initial temperature difference
(C) The time taken to attain 63.2% of the value of initial temperature difference
(D) Determined by the time taken to reach 100°C from 0°C
Answer:(C) The time taken to attain 63.2% of the value of initial temperature difference
Q8. Which of the following has maximum value of thermal conductivity?
(A) Aluminium
(B) Steel
(C) Brass
(D) Copper
Answer: (A) Aluminium
Q9. Heat conducted through per unit area and unit thick face per unit time when temperature difference between opposite faces is unity, is called
(A) Thermal resistance
(B) Thermal coefficient
(C) Temperature gradient
(D) Thermal conductivity
Answer: (D) Thermal conductivity
Q10. Fourier’s law of heat conduction is valid for
(A) One dimensional cases only
(B) Two dimensional cases only
(C) Three dimensional cases only
(D) Regular surfaces having non-uniform temperature gradients
Answer: (A) One dimensional cases only
Q11. The energy distribution of an ideal reflector at higher temperatures is largely in the range of
(A) Shorter wavelength
(B) Longer wavelength
(C) Remain same at all wavelengths
(D) Wavelength has nothing to do with it
Answer: (A) Shorter wavelength
Q12. The ratio of the emissive power and absorptive power of all bodies is the same and is equal to the emissive power of a perfectly black body. This statement is known as
(A) Kirchoff’s law
(B) Stefan’s law
(C) Wien’ law
(D) Planck’s law
Answer: (A) Kirchoff’s law
Q13. The highest thermal diffusivity is of
(A) Iron
(B) Lead
(C) Concrete
(D) Wood
Answer: (B) Lead
Q14. A designer chooses the values of fluid flow rates and specific heats in such a manner that the heat capacities of the two fluids are equal. A hot fluid enters the counter flow heat exchanger at 100°C and leaves at 60°C. A cold fluid enters the heat exchanger at 40°C. The mean temperature difference between the two fluids is
(A) 20°C
(B) 40°C
(C) 60°C
(D) 66.7°C
Answer: (A) 20°C
Q15. The process of heat transfer from one particle of the body to another is called conduction, when the particles of the body
(A) Move actually
(B) Do not move actually
(C) Affect the intervening medium
(D) Does not affect the intervening medium
Answer: (B) Do not move actually
Q16. In free convection heat transfer transition from laminar to turbulent flow is governed by the critical value of the
(A) Reynold’s number
(B) Grashoff’s number
(C) Reynold’s number, Grashoff’s number
(D) Prandtl number, Grashoff’s number
Answer: (D) Prandtl number, Grashoff’s number
Q17. The thickness of thermal and hydrodynamic boundary layer is equal if Prandtl number is
(A) Equal to one
(B) Greater than one
(C) Less than one
(D) Equal to Nusselt number
Answer: (A) Equal to one
Q18. The natural convection air cooled condensers are used in
(A) Domestic refrigerators
(B) Water coolers
(C) Room air conditioners
(D) All of these
Answer: (A) Domestic refrigerators
Q19. The logarithmic mean temperature difference ™ is given by (where Δt1 and Δt2 are temperature differences between the hot and cold fluids at entrance and exit)
(A) tm = (Δt1 – Δt2)/ loge (Δt1/Δt2)
(B) tm = loge (Δt1/Δt2)/ (Δt1 – Δt2)
(C) tm = tm = (Δt1 – Δt2) loge (Δt1/Δt2)
(D) tm = loge (Δt1 – Δt2)/ Δt1/Δt2
Answer: (A) tm = (Δt1 – Δt2)/ loge (Δt1/Δt2)
Q20. The value of the wave length for maximum emissive power is given by
(A) Kirchhoff’s law
(B) Stefan’s law
(C) Wine’s law
(D) Planck’s law
Answer: (C) Wine’s law
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Heat and Mass Transfer – Set 05
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Heat and Mass Transfer – Set 07
Heat and Mass Transfer – Set 08