Heat Transfer (3151909) MCQ

MCQs of Transient Heat Conduction

MCQ No - 1

According to lumped system analysis, solid possesses thermal conductivity that is

(A)

Infinitely large

(B)

Infinitely small

(C)

Moderate

(D)

50% small


A
MCQ No - 2

Glass spheres of 2 mm radius and at 500 degree Celsius is to be cooled by exposing them to an air stream at 25 degree Celsius. Find the minimum time required for cooling to a temperature of 60 degree Celsius. Assume the following property values
Density = 2250 kg/m3
Specific heat = 850 J/kg K
Conductivity = 1.5 W/m K

(A)

13.78 seconds

(B)

14.78 seconds

(C)

15.78 seconds

(D)

16.78 seconds


B
MCQ No - 3

Which is true regarding lumped system analysis?
(i) Conductive resistance = 0
(ii) Convective resistance = 0
(iii) Thermal conductivity = 0
(iv) Thermal conductivity = infinity
Identify the correct statements

(A)

i and ii

(B)

 i, ii and iv

(C)

i and iv

(D)

 ii and iv


C
MCQ No - 4

What is the value of characteristics length for the cylinder?

(A)

R/5

(B)

R/4

(C)

R/3

(D)

R/2


D
MCQ No - 5

What is the criterion for the applicability of lump system analysis?

(A)

Mean length

(B)

Normal length

(C)

Characteristics length

(D)

Mass no


C