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CONVECTION MULTIPLE CHOICE QUESTIONS (MCQ) WITH ANSWERS

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CONVECTION MULTIPLE

CHOICE QUESTIONS

(MCQ) WITH ANSWERS

MCQ increase understanding of basic

concepts. It increases the clarity. Then it

becomes easy to apply the fundamentals

in real life.

  1. Free convection is due to

(a) Inertia force

(b) Viscous force

(c) Buoyancy force

(d) None

ANS: (c)

2. Free convection is

(a) visible

(b) Invisible

(c) Neither visible nor invisible

(d) None

ANS: (a)

3. Convective heat transfer coefficient in forced convection depends upon

(a) Grashoff’s and Reynolds numbers

(b) Grashoff’s and Prandtl numbers

(c) Prandtl and Reynolds numbers

(d) None

4. Free convection deals with

  • (a) Re and Pr

  • (b) Gr and Re

  • (c) Nu and Re

  • (d) None

  • ANS: (d)

5. Convection is most prominent in

  • (a) Fluids

  • (b) Solids

  • (c) Gases

  • (d) None

  • (Ans: a)

 

  1. Thermal boundary layer is bigger than the hydrodynamic boundary layer when

  • (a) Pr >>1

  • (b) Pr=1

  • (c) Pr <<1

  • (d) None

  • ANS: (c)

  1. Free Convective heat transfer coefficient is

  • (a) Greater than h for forced convection

  • (b) Equal to h for forced convection

  • (c) Less than h for forced convection

  • (d) None

  • ANS: (c)

  1. Reynolds number = 5 x 105

  • (a) Where laminar flow starts

  • (b) Where laminar flow ends

  • (c) Where turbulent flow starts

  • (d) None

  • ANS: (b)

9. Real example of the forced convection is

  • (a) Water moving in a container being heated

  •  (b) Flow of blood in the human body

  •  (c) Flow of water in a river

  •  (d) None

  • ANS: (b)

10. Reynolds number is the ratio of

  • (a) Inertia force/gravitational force

  • (b) Viscous force/inertia force

  • (c) Buoyancy force/viscous force

  • (d) None

  • ANS: (d)

11.Product of Grashoff’s and Prandtl number is used in

  • (a) Forced convection

  • (b) Free convection

  • (c) Free as well as in forced convection

  • (d) None

  • ANS: (b)

12. During free convection , motion is caused by

  • (a) Pump in case of a liquid

  • (b) A blower in case of a gas

  • (c) Buoyancy force

  • (d) None

  • ANS: (c)

13.Practical example of free convective heat transfer is

  • (a) Flow of heat in the evaporator of an air conditioner

  •   (b) Flow of heat in the boiler for making steam

  •  (c) Flow of heat from the car radiator

  •  (d) None

  • ANS: (a)

  1. Forced convection is governed by

(a) Grashoff’s Number

(b) Reynolds Number

(c) Reynolds and Prandtl Number

(d) None

ANS: (b)

  1. Prandtl number will be least for

(a) Water

(b) Air

(c) Liquid metal

(d) None

ANS: (c )

  1. Critical Reynolds number in pipe flow is

(a) 1900

(b) 5 lac

(c) 4000

(d) None

ANS: (d)

  1. Free convection Vs forced convection deals with

(a) (Nu x Pr) Vs (Re x Pr)

(b) (Gr x Pr) Vs (Re x Nu)

(c) (Gr x Pr) Vs (Re x Pr)

(d) None

ANS: (c )

  1. The relation for Prandtl number is

(a) μ k/cp

(b) μ ρ/k

(c) μ Cp/k

(d) None

ANS: (c )

  1. Grashoff’s Number is

(a)Inertia force)/Viscous force

(b) (Inertia force x Buoyancy force)2/(Viscous force)2

(c) (Inertia force)2 /( Buoyancy force x Viscous force)

 (d) None

  • ANS: (b)

20. Reynolds number is given by

  • (a) (Inertia force x Buoyancy force)/(Viscous force)2

  • (b) Viscous force/inertia force

  • (c) Inertia force/viscous force

  •  (d) None

  • ANS: (c )

21. Definition of Prandtl number is the ratio of

  • (a) Thermal conductivity/Thermal diffusivity

  •  (b) Thermal diffusivity/Thermal conductivity,

          © Thermal diffusivity/Momentum diffusivity

         (d) None

      ANS: (c )

 

https://www.mesubjects.net/wp-admin/post.php?post=2742&action=edit          Q. ANS. CONVECTION

https://www.mesubjects.net/wp-admin/post.php?post=630&action=edit     CONVECTION HEAT TRANSFER

 

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