Heat Transfer 4

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Mechanical Engineering MCQ Question Papers: DRDO, ISRO, Interview

Subject: Heat Transfer 4

Part 4: List for questions and answers of Heat Transfer

Q1.The radiation takes place
a) Through molecular communication
b) Through vacuum
c) Both a. And b
d) None of the above

Q2.Which phenomenon is related to the term radiation?
a) Magnetic phenomenon
b) Gravity
c) Electromagnetic phenomenon
d) None of the above

Q3.Thermal radiation takes place from a body by electromagnetic waves as a result of
a) The weight of the body
b) The magnetic power of the body
c) The temperature of the body
d) None of the above

Q4.The range of waves within which all possible frequencies of electromagnetic radiation are represented is called as
a) Electromagnetic frequencies
b) Electromagnetic spectrum
c) Electromagnetic range
d) None of the above

Q5.What is the approximate wavelength range of thermal radiation?
a) 0.1 to 100 μm (micrometer)
b) 0.1 to 100 nm (nanometer)
c) 0.1to 100 cm (centimeter)
d) None of the above

Q6.The wavelength range of the visible light is about
a) 350 to 750 μm (micrometer)
b) 350 to 750 nm (nanometer)
c) 350 to 750 cm (centimeter)
d) None of the above

Q7.Which of the following bodies will not be able to emit radiation continuously?
a) A body with very high temperature placed in air medium
b) A body with temperature 0 deg. C placed in air medium
c) A body with temperature 0 deg. C placed in vacuum
d) None of the above

Q8.When a body receives radiation in the wavelength range of 0.1 to 100 μm (micrometer), then its temperature
a) Increases
b) Decreases
c) Does not change
d) Unpredictable

Q9.What is emissive power of a body?
a) Total radiation emitted by the body per unit volume and time
b) Total radiation emitted by the body per unit temperature and time
c) Total radiation emitted by the body per unit area and time
d) None of the above

Q10.The emissive power of a body depends upon
a) Temperature of the the body
b) Characteristics of the surface of the body
c) Both a. And b
d) None of the above

Q11.At a given temperature if wavelengths are changed, the quality of radiation per unit wavelength
a) Will always be constant
b) Will also be changed
c) Will be changed sometimes but sometimes be constant
d) Unpredictable

Q12.What is the relation between reflectivity (ρ), absorptivity (α) and transmissivity (τ)?
a) Ρ – α + τ = 1
b) Ρ + α – τ = 1
c) Ρ + α + τ = 1
d) Ρ – α – τ = 1

Q13.What is the opaque body?
a) The body which does not reflect radiation
b) The body which does not absorb radiation
c) The body which does not transmit radiation
d) All of the above

Q14.What is diffuse reflection of radiation?
a) The reflection of radiation on a rough surface which occurs in all directions
b) The reflection of radiation on a rough surface which occurs in a single direction
c) The reflection of radiation on a smooth surface
d) None of the above

Q15.The reflection in which the angle of incident is equal to the angle of reflection is called as
a) Regular reflection
b) Specular reflection
c) Both a. And b
d) None of the above

Q16.The values of reflectivity (ρ), absorptivity (α) and transmissivity (τ) of a body are depend upon
a) Material of the body
b) Surface condition of the body
c) Wavelength of radiation
d) All of the above

Q17.What is the black body or an ideal radiator?
a) The body which transmits all the radiations incident upon it
b) The body which absorbs all the radiations incident upon it
c) The body which reflects all the radiations incident upon it
d) None of the above

Q18.As a radiator, the black body emits the maximum possible thermal radiation
a) At a constant single wavelength
b) At the maximum wavelength
c) At all wavelengths
d) None of the above

Q19.The emissivity (ε) can be defined as the ratio of
a) Emissive power of real body to the emissive power of black body
b) Emissive power of black body to the emissive power of real body
c) Reflectivity of real body to emissive power of black body
d) Reflectivity of black body to emissive power of real body

Q20.Stefan-Boltzmann law states that the energy radiated per unit area per unit time by the black body is
a) Directly proportional to the square of the temperature of the black body
b) Inversely proportional to the square of the temperature of the black body
c) Directly proportional to the forth power of the temperature of the black body
d) Inversely proportional to the fourth power of the temperature of the black body

Part 4: List for questions and answers of Heat Transfer

Q1. Answer: b

Q2. Answer: c

Q3. Answer: c

Q4. Answer: b

Q5. Answer: a

Q6. Answer: b

Q7. Answer: d

Q8. Answer: a

Q9. Answer: c

Q10. Answer: c

Q11. Answer: b

Q12. Answer: c

Q13. Answer: c

Q14. Answer: a

Q15. Answer: c

Q16. Answer: d

Q17. Answer: b

Q18. Answer: c

Q19. Answer: a

Q20. Answer: c