Explore topic-wise MCQs in GATE (Mechanical Engineering).

This section includes 968 Mcqs, each offering curated multiple-choice questions to sharpen your GATE (Mechanical Engineering) knowledge and support exam preparation. Choose a topic below to get started.

951.

Which of the following is expected to have highest thermal conductivity

A. steam
B. solid ice
C. melting ice
D. water
Answer» C. melting ice
Discussion
952.

Which of the following has least value of conductivity

A. glass
B. water
C. plastic
D. air.
Answer» E.
Discussion
953.

The amount of heat flow through a body by conduction is

A. directly proportional to the surface area of the body
B. directly proportional to the temperature difference on the two faces of the body
C. dependent upon the material of the body
D. all of the above.
Answer» E.
Discussion
954.

Heat flows from one body to other when they have

A. different heat contents
B. different specific heat
C. different atomic structure
D. different temperatures
Answer» E.
Discussion
955.

Thermal conductivity of air with rise in temperature

A. increases
B. decreases
C. remains constant
D. may increase or decrease depending on temperature
Answer» B. decreases
Discussion
956.

The time constant of a thermocouple is

A. the time taken to attain the final temperature to be measured
B. the time taken to attain 50% of the value of initial temperature difference
C. the time taken to attain 63.2% of the value of initial temperature difference
D. determined by the time taken to reach 100°C from 0°C
Answer» D. determined by the time taken to reach 100°C from 0°C
Discussion
957.

Thermal conductivity of water at 20°C is of the order of

A. 0.1
B. 0.23
C. 0.42
D. 0.51
Answer» E.
Discussion
958.

Thermal conductivity of water in general with rise in temperature

A. increases
B. decreases
C. remains constant
D. may increase or decrease depending on temperature
Answer» E.
Discussion
959.

Cork is a good insulator because it has

A. free electrons
B. atoms colliding frequency
C. low density
D. porous body
Answer» E.
Discussion
960.

Metals are good conductors of heat because

A. their atoms collide frequently
B. their atoms-are relatively far apart
C. they contain free electrons
D. they have high density
Answer» B. their atoms-are relatively far apart
Discussion
961.

Pick up the wrong case. Heat flowing from one side to other depends directly on

A. face area
B. time
C. thickness
D. temperature difference
Answer» D. temperature difference
Discussion
962.

Heat transfer in liquid and gases takes place by

A. conduction
B. convection
C. radiation
D. None of the above
Answer» C. radiation
Discussion
963.

When heat is Transferred by molecular collision, it is referred to as heat transfer by

A. conduction
B. convection
C. radiation
D. scattering
Answer» C. radiation
Discussion
964.

The insulation ability of an insulator with the presence of moisture would

A. increase
B. decrease
C. remain unaffected
D. may increase/decrease depending on temperature and thickness of insulation
Answer» C. remain unaffected
Discussion
965.

When heat is transferred from one particle of hot body to another by actual motion of the heated particles, it is referred to as heat transfer by

A. conduction
B. convection
C. radiation
D. conduction and convection
Answer» B. convection
Discussion
966.

Heat transfer takes place as per-

A. zeroth law of thermodynamics
B. first law of thermodynamic
C. second law of the thermodynamics
D. Kirchoffs law (e) Stefans law.
Answer» D. Kirchoffs law (e) Stefans law.
Discussion
967.

Thermal conductivity of non-metallic amorphous solids with decrease in temperature

A. increases
B. decreases
C. remains constant
D. may increase or decrease depending on temperature
Answer» C. remains constant
Discussion
968.

Unit of thermal conductivity in M.K.S. units is`

A. kcal/kg m2 °C
B. kcal-m/hr m2 °C
C. kcal/hr m2 °C
D. kcal-m/hr °C
Answer» C. kcal/hr m2 °C
Discussion