Mechanical Engineering MCQ Question Papers: DRDO, ISRO, Interview

Subject: Heat Transfer 1

**Part 1: List for questions and answers of Heat Transfer**

**Q1.Why is the negative sign introduced in the equation of Fourier’s law of heat conduction?**

a) Because heat transfer rate is inversely proportional to temperature gradient

b) Because value of thermal conductivity k is negative

c) Because heat is transferred from higher temperature to lower temperature

d) None of the above

**Q2.The cooling of a metal ball of volume V, in large quantity of fluid is analogous to**

a) Discharging of battery in an electric system

b) Discharging of capacitor in an electric system

c) Generation of heat in resistor in an electrical system

d) None of the above

**Q3.What should be the Biot number to assume the body at uniform temperature?**

a) The Biot number should be less than 0.1

b) The Biot number should be more than 0.1

c) The Biot number should be equal to 0.1

d) None of the above

**Q4.What is the correct formula for The Biot number?**

a) Hl/k

b) K/hl

c) L/hk

d) Hk/l

**Q5.The Biot number or Biot modulus is given by**

a) The ratio of external convection resistance to the internal conduction resistance

b) The ratio of internal conduction resistance to the external convection resistance

c) Multiplying internal conduction resistance and external convection resistance

d) None of the above

**Q6.What is lumped heat capacity analysis?**

a) The analysis of a system in which it is assumed to be at no uniform temperature

b) The analysis of a system in which it is assumed to be at uniform temperature

c) The analysis of a system in which it is assumed to be at either uniform or no uniform temperature

d) None of the above

**Q7.Suppose that a hot metal ball is immersed in cold water, then temperature distribution in the body depends upon**

a) Thermal conductivity of the body

b) Convective heat transfer from the body surface to water

c) Both a and b

d) None of the above

**Q8.Generally the external thermal resistance between the surface of the body and the environment is**

a) Less than the internal conduction resistance in the body

b) More than the internal conduction resistance in the body

c) Same as the internal conduction resistance in the body

d) None of the above

**Q9.When does the general heat conduction equation which gives the temperature ****distribution and conduction heat flow in an isotropic solid reduces to Laplace equation?**

a) If the body or element is in unsteady-state with heat generation

b) If the body or element is in steady-state with heat generation

c) If the body or element is in unsteady-state with no heat generation

d) If the body or element is in steady-state with no heat generation

**Q10.According to the Fourier’s law of heat conduction, the rate of heat transfer by ****conduction depends upon**

a) Area of cross section normal to the heat flow

b) Temperature gradient

c) Both a and b

d) None of the above

**Q11.The value of thermal conductivity k depends upon**

a) The material through which the heat is transferred

b) The intensity of heat energy which is being transferred

c) The area which is parallel to the heat transfer

d) All of the above

**Q12.The materials which have low thermal conductivity are called as**

a) Thermal conductors

b) Thermal resistors

c) Thermal insulators

d) None of the above

**Q13.How does the radiation heat transfer occur through perfect vacuum?**

a) By light waves

b) By electromagnetic waves

c) Both a. And b

d) None of the above

**Q14.The Stefan-Boltzmann law of thermal radiation is applicable for**

a) White body

b) Gray body

c) Black body

d) All the bodies

**Q15.According to the Stefan-Boltzmann law of thermal radiation for a perfect radiator, the rate of radiant energy per unit area is proportional to**

a) The temperature of that radiator

b) The square of the temperature of that radiator

c) The cube of the temperature of that radiator

d) The fourth power of the temperature of that radiator

**Q16.Gray body can emits radiation**

a) At higher rate than the black body

b) At lower rate than the black body

c) At equal rate than the black body

d) Cannot predict

**Q17.What should be the temperature of black body to emit radiant energy which is ****independent of the conditions in the surroundings?**

a) Temperature of black body should be less than zero

b) Temperature of black body should be more than zero

c) Temperature of black body should be equal to zero

d) All of the above

**Q18.What is the mode of heat transfer from the hot surface to the adjacent layer of fluid which surrounds the surface?**

a) Conduction mode of heat transfer

b) Radiation mode of heat transfer

c) Convection mode of heat transfer

d) None of the above

**Q19.Convective heat transfer coefficient is also known as**

a) Film convection factor

b) Film coefficient

c) Film conductance

d) None of the above

**Q20.The term in the heat transfer system which is analogous to the electrical resistance is called as**

a) Thermal resistance

b) Conductive resistance

c) Potential resistance

d) None of the above

**Part 1: List for questions and answers of Heat Transfer**

Q1. Answer: a

Q2. Answer: b

Q3. Answer: b

Q4. Answer: a

Q5. Answer: b

Q6. Answer: a

Q7. Answer: c

Q8. Answer: b

Q9. Answer: b

Q10. Answer: c

Q11. Answer: a

Q12. Answer: c

Q13. Answer: c

Q14. Answer: c

Q15. Answer: d

Q16. Answer: b

Q17. Answer: b

Q18. Answer: a

Q19. Answer: c

Q20. Answer: a