Convective Heat Transfer MCQs

Welcome to our comprehensive collection of Multiple Choice Questions (MCQs) on Convective Heat Transfer, a fundamental topic in the field of Heat Transfer. Whether you're preparing for competitive exams, honing your problem-solving skills, or simply looking to enhance your abilities in this field, our Convective Heat Transfer MCQs are designed to help you grasp the core concepts and excel in solving problems.

In this section, you'll find a wide range of Convective Heat Transfer mcq questions that explore various aspects of Convective Heat Transfer problems. Each MCQ is crafted to challenge your understanding of Convective Heat Transfer principles, enabling you to refine your problem-solving techniques. Whether you're a student aiming to ace Heat Transfer tests, a job seeker preparing for interviews, or someone simply interested in sharpening their skills, our Convective Heat Transfer MCQs are your pathway to success in mastering this essential Heat Transfer topic.

Note: Each of the following question comes with multiple answer choices. Select the most appropriate option and test your understanding of Convective Heat Transfer. You can click on an option to test your knowledge before viewing the solution for a MCQ. Happy learning!

So, are you ready to put your Convective Heat Transfer knowledge to the test? Let's get started with our carefully curated MCQs!

Convective Heat Transfer MCQs | Page 3 of 7

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Q21.
Newton-Rikhman law is given by

a.

Q = h A (t s – t f)

b.

Q = 2 h A (t s – t f)

c.

Q = 3 h A (t s – t f)

d.

Q = 4 h A (t s – t f)

Discuss
Answer: (a).Q = h A (t s – t f)
Q22.
The value of film coefficient is dependent upon

(i) Boundary layer configuration
(ii) Geometry and orientation of the surface
(iii) Surface conditions

a.

1 and 2

b.

2 and 3

c.

1 and 2

d.

1, 2 and 3

Discuss
Answer: (d).1, 2 and 3
Q23.
The convection coefficients for boiling and condensation lie in the range

a.

5000-12500 W/m 2 K

b.

2500-100000 W/m 2 K

c.

2500-5000 W/m 2 K

d.

2500-12500 W/m 2 K

Discuss
Answer: (b).2500-100000 W/m 2 K
Q24.
Forced air flows over a convection heat exchanger in a room heater, resulting in a convective heat transfer coefficient 1.136 k W/m² K. The surface temperature of heat exchanger may be considered constant at 65 degree Celsius, and the air is at 20 degree Celsius. Determine the heat exchanger surface area required for 8.8 k W of heating

a.

0.272 m²

b.

0.472 m²

c.

0.172 m²

d.

0.672 m²

Discuss
Answer: (c).0.172 m²
Q25.
A region of fluid motion near a plate in which temperature gradient exist is

a.

Thermal boundary layer

b.

Diathermia boundary layer

c.

Turbulent flow

d.

Laminar flow

Discuss
Answer: (a).Thermal boundary layer
Q26.
Thermo-physical properties of the fluid are represented by

(i) Density
(ii) Viscosity
(iii) Specific heat
(iv) Thermal conductivity

Identify the correct option

a.

1 and 2

b.

1, 2, 3 and 4

c.

2, 3 and 4

d.

1, 2 and 3

Discuss
Answer: (b).1, 2, 3 and 4
Q27.
A motor cycle cylinder consists of ten fins, each 150 mm outside diameter and 75 mm inside diameter. The average fin temperature is 500 degree Celsius and the surrounding air is at 20 degree Celsius temperature. Make calculations for the rate of heat dissipation from the cylinder fins by convection when motor cycle is stationary and convective coefficient is 6 W/m² K

a.

432.2 W

b.

532.2 W

c.

632.2 W

d.

763.2 W

Discuss
Answer: (d).763.2 W
Q28.
Air at 20 degree Celsius flows over a flat surface maintained at 80 degree Celsius. The local heat flow at a point was measured as 1250 W/m² .Take thermal conductivity of air as 0.028 W/m K, calculate the temperature at a distance 0.5 mm from the surface

a.

57.682 degree celsius

b.

67.682 degree celsius

c.

77.682 degree celsius

d.

87.682 degree celsius

Discuss
Answer: (a).57.682 degree celsius
Q29.
The convective heat transfer coefficient in laminar flow over a flat plate

a.

Increases with distance

b.

Increases if a higher viscosity fluid is used

c.

Increases if a denser fluid is used

d.

Decreases with increase in free stream velocity

Discuss
Answer: (c).Increases if a denser fluid is used
Q30.
For laminar flow over a flat plate, the average value of Nusselt number is prescribed by the relation

Nu = 0.664 (Re)^0.5 (Pr)^0.33

Which of the following is then a false statement?

a.

Density has to be increased four times

b.

Plate length has to be decreased four times

c.

Specific heat has to be increased four times

d.

Dynamic viscosity has to be decreased sixteen times

Discuss
Answer: (d).Dynamic viscosity has to be decreased sixteen times
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