Question 1

In case the hydrodynamic and thermal boundary layers are identical for a fluid flowing over a heated plate

Accepted Answer

A) The value of Prandtl number must be 0.5 
B) The plate surface must be smooth 
C) The plate must be of low thermal conductivity 
D) The value of Prandtl number thust be 1 
E) The value of Prandtl number must be zero 
A) The value of Prandtl number must be 0.5 
B) The plate surface must be smooth 
C) The plate must be of low thermal conductivity 
D) The value of Prandtl number thust be 1 
E) The value of Prandtl number must be zero D

Question 2

Ditus Boelter equation is applicable in case of fluids flowing in

Accepted Answer

A) Laminar region 
B) Turbulent region 
C) Transition region 
D) Any of the above 
E) None of the above 
A) Laminar region 
B) Turbulent region 
C) Transition region 
D) Any of the above 
E) None of the above B

Question 3

Transient heat flow occurs in

Accepted Answer

A) Cooling of casting 
B) Heating and cooling of buildings due to sun 
C) Electric conductors carrying current 
D) Melting of ice 
E) Insulated pipes carrying superheated steam 
A) Cooling of casting 
B) Heating and cooling of buildings due to sun 
C) Electric conductors carrying current 
D) Melting of ice 
E) Insulated pipes carrying superheated steam B

Question 4

All bodies above absolute zero temperature emit radiation". Above statement is based on

Accepted Answer

A) D'Alambert's rule 
B) Wein's law 
C) Stefan law 
D) Planck's law 
E) Prevost theory 
A) D'Alambert's rule 
B) Wein's law 
C) Stefan law 
D) Planck's law 
E) Prevost theory

Question 5

Hydrogen cannot be liquefied at room temperature because

Accepted Answer

A) it is a diatomic gas 
B) its critical temperature is less than the room temperature 
C) 37,500 kg 
D) it has low density 
E) it has high specific heat 
A) it is a diatomic gas 
B) its critical temperature is less than the room temperature 
C) 37,500 kg 
D) it has low density 
E) it has high specific heat

Question 6

Unsaturated vapours

Accepted Answer

A) Do not obey gas laws 
B) Fully obey gas laws 
C) Obey Boyle's law but not Charle's law 
D) Partly obey gas laws depending upon the degree of unsaturations 
E) None of the above 
A) Do not obey gas laws 
B) Fully obey gas laws 
C) Obey Boyle's law but not Charle's law 
D) Partly obey gas laws depending upon the degree of unsaturations 
E) None of the above

Question 7

If the roof of a house is painted with a shiny metallic paint, the temperature inside will

Accepted Answer

A) Rise 
B) Fall 
C) Remain unchanged 
D) Depends on other factors 
E) None of the above 
A) Rise 
B) Fall 
C) Remain unchanged 
D) Depends on other factors 
E) None of the above

Question 8

Plank's law of radiation is applicable to

Accepted Answer

A) Radiation of any kind 
B) Temperature radiation 
C) Monochromatic radiation 
D) Thermal radiation 
E) None of the above 
A) Radiation of any kind 
B) Temperature radiation 
C) Monochromatic radiation 
D) Thermal radiation 
E) None of the above

Question 9

Which of the following has the highest value of the thermal conductivity

Accepted Answer

A) Wood 
B) Asbestos 
C) Nichrome 
D) Clay 
E) Refractory brick 
A) Wood 
B) Asbestos 
C) Nichrome 
D) Clay 
E) Refractory brick

Question 10

Diffusion coefficient of water into air at 26°C is nearly

Accepted Answer

A) 5.2 cm2/s 
B) 2.6 cm2/sec 
C) 0.026 cm2/s 
D) 2.6 cm2/s 
E) 0.26 cm2/s 
A) 5.2 cm2/s 
B) 2.6 cm2/sec 
C) 0.026 cm2/s 
D) 2.6 cm2/s 
E) 0.26 cm2/s

Question 11

Which of the following is wrong

Accepted Answer

A) Black surfaces are better absorbers than white ones 
B) Black surfaces are better radiators than white ones 
C) Rough surfaces are better radiators than smooth surfaces 
D) 37,500 kg 
E) Highly polished mirror like surfaces are very good radiators 
A) Black surfaces are better absorbers than white ones 
B) Black surfaces are better radiators than white ones 
C) Rough surfaces are better radiators than smooth surfaces 
D) 37,500 kg 
E) Highly polished mirror like surfaces are very good radiators

Question 12

A dimensionless number which is the ratio of mass heat flow rate to the heat flow rate by conduction under a unit temperature gradient and through a thickness L is known as

Accepted Answer

A) Nusselt number 
B) Prandtl number 
C) Weber number 
D) Grashof number 
E) Peclet number 
A) Nusselt number 
B) Prandtl number 
C) Weber number 
D) Grashof number 
E) Peclet number

Question 13

Formation of fog is due to

Accepted Answer

A) High pressure 
B) Humidity 
C) Temperature fall of atmosphere 
D) Low pressure 
E) Night showers 
A) High pressure 
B) Humidity 
C) Temperature fall of atmosphere 
D) Low pressure 
E) Night showers

Question 14

The phenomenon of boiling the milk in an open container when milk spills over the vessel is termed as

Accepted Answer

A) Film boiling 
B) Pool boiling 
C) Sub-cooled boiling 
D) Interface evaporation 
E) Nuclear boiling 
A) Film boiling 
B) Pool boiling 
C) Sub-cooled boiling 
D) Interface evaporation 
E) Nuclear boiling

Question 15

In case of natural covection, the Nusselt number is function of

Accepted Answer

A) Reynolds number 
B) Reynolds number and Prandtl number 
C) Grashof's number and Prandtl number 
D) Weber number and Mach number 
E) None of the above 
A) Reynolds number 
B) Reynolds number and Prandtl number 
C) Grashof's number and Prandtl number 
D) Weber number and Mach number 
E) None of the above

Question 16

Which dimensionless number indicates the relative strength of the buoyant to viscous forces?

Accepted Answer

A) Froude's number 
B) 37,500 kg 
C) Prandtl number 
D) Weber number 
E) Grashoff number 
A) Froude's number 
B) 37,500 kg 
C) Prandtl number 
D) Weber number 
E) Grashoff number

Question 17

The surface temperatures of a flat wall are 650°C and 450°C respectively and the thermal conductivity of the wall material is 0.30 kcal/m-hr-°C. The heat flux for a wall of 20 cm thickness will be

Accepted Answer

A) 60 kcal/m2-hr 
B) 600 kcal/m2-hr 
C) 120 kcal/m2-hr 
D) 300 kcal/m2-hr 
E) 450 kcal/m2-hr 
A) 60 kcal/m2-hr 
B) 600 kcal/m2-hr 
C) 120 kcal/m2-hr 
D) 300 kcal/m2-hr 
E) 450 kcal/m2-hr

Question 18

If the amount of radiant energy received per unit area per second from the sun is measured at the Earth, Mars and Jupiter it will be

Accepted Answer

A) in the decreasing order - Jupiter, Mars, Earth 
B) in the increasing order - Jupiter, Mars, Earth 
C) identical on all the three planets 
D) 37,500 kg 
E) in the increasing order - Earth, Mars, Jupiter 
A) in the decreasing order - Jupiter, Mars, Earth 
B) in the increasing order - Jupiter, Mars, Earth 
C) identical on all the three planets 
D) 37,500 kg 
E) in the increasing order - Earth, Mars, Jupiter

Question 19

In a psychrometric chart the abscissa represents

Accepted Answer

A) Specific humidity 
B) Relative humidity 
C) Enthalpy 
D) Dry bulb temperature 
E) Wet bulb temperature 
A) Specific humidity 
B) Relative humidity 
C) Enthalpy 
D) Dry bulb temperature 
E) Wet bulb temperature

Question 20

Transformer oil having kinematic viscosity of 3.66 x 10-6 m2/s flows through a tube 8 mm diameter at velocity of 0.6 m/s. The value of Reynolds number of flow would be

Accepted Answer

A) 1510 
B) 1625 
C) 1000 
D) 1310 
E) 1415 
A) 1510 
B) 1625 
C) 1000 
D) 1310 
E) 1415

Exam 14: Components of Radiation From Flames

In case the hydrodynamic and thermal boundary layers are identical for a fluid flowing over a heated plate

Ditus Boelter equation is applicable in case of fluids flowing in

Transient heat flow occurs in

All bodies above absolute zero temperature emit radiation". Above statement is based on

Hydrogen cannot be liquefied at room temperature because

Unsaturated vapours

If the roof of a house is painted with a shiny metallic paint, the temperature inside will

Plank's law of radiation is applicable to

Which of the following has the highest value of the thermal conductivity

Diffusion coefficient of water into air at 26°C is nearly

Which of the following is wrong

A dimensionless number which is the ratio of mass heat flow rate to the heat flow rate by conduction under a unit temperature gradient and through a thickness L is known as

Formation of fog is due to

The phenomenon of boiling the milk in an open container when milk spills over the vessel is termed as

In case of natural covection, the Nusselt number is function of

Which dimensionless number indicates the relative strength of the buoyant to viscous forces?

The surface temperatures of a flat wall are 650°C and 450°C respectively and the thermal conductivity of the wall material is 0.30 kcal/m-hr-°C. The heat flux for a wall of 20 cm thickness will be

If the amount of radiant energy received per unit area per second from the sun is measured at the Earth, Mars and Jupiter it will be

In a psychrometric chart the abscissa represents

Transformer oil having kinematic viscosity of 3.66 x 10-6 m2/s flows through a tube 8 mm diameter at velocity of 0.6 m/s. The value of Reynolds number of flow would be

Thermal Conductivity and Heat Transfer

Heat Transfer and Thermal Conductivity: Part A

Heat Transfer and Thermal Conductivity: Part B

Heat Transfer and Thermal Conductivity: Part C

Heat Transfer and Evaporator

Heat Transfer and Heat Exchangers: Part A

Heat Transfer and Heat Exchangers: Part B

Heat Transfer and Crystallisation

Heat Transfer and Thermal Properties: Part A

Heat Transfer and Thermal Properties: Part B

Heat Exchangers and Condensation

Thermal Properties and Processes

Concepts in Heat Transfer

Heat Transfer and Thermodynamics

Heat Transfer Processes, Thermometers, and Evaporators

Heat Transfer and Thermal Properties: Part A

Heat Transfer Mechanisms in a Spaced Plate System

Heat Transfer and Evaporation

Understanding the Dominant Mechanism of Heat Transfer

Heat Transfer and Fluid Mechanics

Heat Transfer and Boiling Point Elevation in Solutions

Filters

Transformer oil having kinematic viscosity of 3.66 x 10-6 m²/s flows through a tube 8 mm diameter at velocity of 0.6 m/s. The value of Reynolds number of flow would be