Thermal conductivity of wood depends on

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Thermal conductivity of wood depends on

A. Moisture

B. Density

C. Temperature

D. All of the above

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Cork is a good insulator because it has

A. Free electrons

B. Atoms colliding frequency

C. Low density

D. Porous body

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The ratio of the energy absorbed by the body to total energy falling on it is called

A. Absorptive power

B. Emissive power

C. Absorptivity

D. Emissivity

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The unit of overall coefficient of heat transfer is

A. W/m²K

B. W/m²

C. W/mK

D. W/m

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In convection heat transfer from hot flue gases to water tube, even though flow may be turbulent, a laminar flow region (boundary layer of film) exists close to the tube. The heat transfer through this film takes place by

A. Convection

B. Radiation

C. Conduction

D. Both convection and conduction

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The heat of sun reaches to us according to

A. Conduction

B. Convection

C. Radiation

D. None of these

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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

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In heat exchangers, degree of approach is defined as the difference between temperatures of

A. Cold water inlet and outlet

B. Hot medium inlet and outlet

C. Hot medium outlet and cold water inlet

D. Hot medium outlet and cold water outlet

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Thermal conductivity of water in general with rise in temperature

A. Increases

B. Decreases

C. Remain constant

D. May increase or decrease depending on temperature

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According to Newton's law of cooling, the heat transfer from a hot body to a cold body is

A. Directly proportional to the surface area

B. Directly proportional to the difference of temperatures between the two bodies

C. Either (A) or (B)

D. Both (A) and (B)

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Unit of thermal diffusivity is

A. m²/hr

B. m²/hr °C

C. kcal/m² hr

D. kcal/m. hr °C

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The thermal diffusivities for gases are generally

A. More than those for liquids

B. Less than those for liquids

C. More than those for solids

D. Dependent on the viscosity

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The most commonly used method for the design of duct size is the

A. Velocity reduction method

B. Equal friction method

C. Static regains method

D. Dual or double method

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Free convection flow depends on

A. Density

B. Coefficient of viscosity

C. Gravitational force

D. All of these

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Thermal conductivity of wood depends on

A. Moisture

B. Density

C. Temperature

D. All of the above

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

A. Increases

B. Decreases

C. Remain constant

D. May increase or decrease depending on temperature

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Depending on the radiating properties, body will be transparent when

A. P = 0, x = 0 and a = 1

B. P=1, x = 0, and a = 0

C. P = 0, T= 1, and a = 0

D. X = 0, a + p = 1

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Total emissivity of polished silver compared to black body is

A. Same

B. Higher

C. More or less same

D. Very much lower

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A perfect black body is one which

A. Is black in colour

B. Reflects all heat

C. Transmits all heat radiations

D. Absorbs heat radiations of all wave lengths falling on it

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A composite slab has two layers of different materials with thermal conductivities k₁ and k₂. If each layer has the same thickness, then the equivalent thermal conductivity of the slab will be

A. k₁ k₂

B. (k₁ + k₂)

C. (k₁ + k₂)/ k₁ k₂

D. 2 k₁ k₂/ (k₁ + k₂)

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The heat transfer by conduction through a thick sphere is given by

A. Q = 2πkr₁ r₂ (T₁ - T₂)/ (r₂ - r₁)

B. Q = 4πkr₁ r₂ (T₁ - T₂)/ (r₂ - r₁)

C. Q = 6πkr₁ r₂ (T₁ - T₂)/ (r₂ - r₁)

D. Q = 8πkr₁ r₂ (T₁ - T₂)/ (r₂ - r₁)

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The expression Q = ρ AT⁴ is called

A. Fourier equation

B. Stefan-Boltzmann equation

C. Newton Reichmann equation

D. Joseph-Stefan equation

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According to Stefan Boltzmann law, ideal radiators emit radiant energy at a rate proportional to

A. Absolute temperature

B. Square of temperature

C. Fourth power of absolute temperature

D. Fourth power of temperature

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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

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

A. 0.1

B. 0.23

C. 0.42

D. 0.51

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The ratio of Nusselt number and the product of Reynold's number and Prandtl number is equal to

A. Stanton number

B. Biot number

C. Peclet number

D. Grashoff number

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Upto the critical radius of insulation,

A. Added insulation will increase heat loss

B. Added insulation will decrease heat loss

C. Convective heat loss will be less than conductive heat loss

D. Heat flux will decrease

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The value of the wavelength for maximum emissive power is given by

A. Wien's law

B. Planck's law

C. Stefan's law

D. Fourier's law

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The unit of Stefan-Boltzmann constant is

A. Watt/mK

B. Watt/m²K²

C. Watt/m²K⁴

D. Watt/mK²

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The heat transfer takes place according to

A. Zeroth law of thermodynamics

B. First law of thermodynamics

C. Second law of thermodynamics

D. Kirchhoff's law

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In a shell and tube heat exchanger, baffles are provided on the shell side to

A. Improve heat transfer

B. Provide support for tubes

C. Prevent stagnation of shell side fluid

D. All of these

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Accepted Answer

D. All of the above

Thermal conductivity of wood depends on

Correct Answer :

Show all Heat & Mass Transfer MCQ

Related Questions

Cork is a good insulator because it has

The ratio of the energy absorbed by the body to total energy falling on it is called

The unit of overall coefficient of heat transfer is

In convection heat transfer from hot flue gases to water tube, even though flow may be turbulent, a laminar flow region (boundary layer of film) exists close to the tube. The heat transfer through this film takes place by

The heat of sun reaches to us according to

The amount of heat flow through a body by conduction is

In heat exchangers, degree of approach is defined as the difference between temperatures of

Thermal conductivity of water in general with rise in temperature

According to Newton's law of cooling, the heat transfer from a hot body to a cold body is

Unit of thermal diffusivity is

The thermal diffusivities for gases are generally

The most commonly used method for the design of duct size is the

Free convection flow depends on

Thermal conductivity of wood depends on

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

Depending on the radiating properties, body will be transparent when

Total emissivity of polished silver compared to black body is

A perfect black body is one which

A composite slab has two layers of different materials with thermal conductivities k₁ and k₂. If each layer has the same thickness, then the equivalent thermal conductivity of the slab will be

The heat transfer by conduction through a thick sphere is given by

The expression Q = ρ AT⁴ is called

According to Stefan Boltzmann law, ideal radiators emit radiant energy at a rate proportional to

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

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

The ratio of Nusselt number and the product of Reynold's number and Prandtl number is equal to

Upto the critical radius of insulation,

The value of the wavelength for maximum emissive power is given by

The unit of Stefan-Boltzmann constant is

The heat transfer takes place according to

In a shell and tube heat exchanger, baffles are provided on the shell side to

Also checkout

Thermal conductivity of wood depends on

Correct Answer :

Show all Heat & Mass Transfer MCQ

Related Questions

Cork is a good insulator because it has

The ratio of the energy absorbed by the body to total energy falling on it is called

The unit of overall coefficient of heat transfer is

In convection heat transfer from hot flue gases to water tube, even though flow may be turbulent, a laminar flow region (boundary layer of film) exists close to the tube. The heat transfer through this film takes place by

The heat of sun reaches to us according to

The amount of heat flow through a body by conduction is

In heat exchangers, degree of approach is defined as the difference between temperatures of

Thermal conductivity of water in general with rise in temperature

According to Newton's law of cooling, the heat transfer from a hot body to a cold body is

Unit of thermal diffusivity is

The thermal diffusivities for gases are generally

The most commonly used method for the design of duct size is the

Free convection flow depends on

Thermal conductivity of wood depends on

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

Depending on the radiating properties, body will be transparent when

Total emissivity of polished silver compared to black body is

A perfect black body is one which

A composite slab has two layers of different materials with thermal conductivities k₁ and k₂. If each layer has the same thickness, then the equivalent thermal conductivity of the slab will be

The heat transfer by conduction through a thick sphere is given by

The expression Q = ρ AT4 is called

According to Stefan Boltzmann law, ideal radiators emit radiant energy at a rate proportional to

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

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

The ratio of Nusselt number and the product of Reynold's number and Prandtl number is equal to

Upto the critical radius of insulation,

The value of the wavelength for maximum emissive power is given by

The unit of Stefan-Boltzmann constant is

The heat transfer takes place according to

In a shell and tube heat exchanger, baffles are provided on the shell side to

Also checkout

The expression Q = ρ AT⁴ is called