Heat transfer takes place as per

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Heat transfer takes place as per

A. Zeroth law of thermodynamics

B. First law of thermodynamic

C. Second law of the thermodynamics

D. Kirchoff's law

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A steam pipe is to be lined with two layers of insulating materials of different thermal conductivities. For the minimum heat transfer,

A. The better insulation must be put inside

B. The better insulation must be put outside

C. One could place either insulation on either side

D. One should take into account the steam temperature before deciding as to which insulation is put where

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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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A designer chooses the values of fluid flow rates and specific heats in such a manner that the heat capacities of the two fluids are equal. A hot fluid enters the counter flow heat exchanger at 100° C and leaves at 60° C. A cold fluid enters the heat exchanger at 40° C. The mean temperature difference between the two fluids is

A. 20°C

B. 40°C

C. 60°C

D. 66.7°C

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Thermal conductivity of glass wool varies from sample to sample because of variation in

A. Composition

B. Density

C. Porosity

D. All of the above

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If the energy radiated per second per sq. cm. of the surface for wave lengths lying between λ, and λ + dλ is represented by (eλ.dλ), then eλ is called

A. Absorptive power

B. Emissive power

C. Emissivity

D. None of these

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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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Temperature of steam at around 540°C can be measured by

A. Thermometer

B. Thermistor

C. Thermocouple

D. None of these

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According to Prevost theory of heat exchange

A. It is impossible to transfer heat from low temperature source to t high temperature source

B. Heat transfer by radiation requires no medium

C. All bodies above absolute zero emit radiation

D. Heat transfer in most of the cases takes place by combination of conduction, convection and radiation

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The logarithmic mean temperature difference (t_m) is given by (where Δt₁ and Δt₂ are temperature differences between the hot and cold fluids at entrance and exit)

A. t_m = (Δt₁ - Δt₂)/ log_e (Δt₁/Δt₂)

B. t_m = log_e (Δt₁/Δt₂)/ (Δt₁ - Δt₂)

C. t_m = t_m = (Δt₁ - Δt₂) log_e (Δt₁/Δt₂)

D. t_m = log_e (Δt₁ - Δt₂)/ Δt₁/Δt₂

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Which of the following is expected to have highest thermal conductivity?

A. Steam

B. Solid ice

C. Melting ice

D. Water

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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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A non-dimensional number generally associated with natural convection heat transfer is

A. Grashoff number

B. Nusselt number

C. Weber number

D. Prandtl number

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Joule sec is the unit of

A. Universal gas constant

B. Kinematic viscosity

C. Thermal conductivity

D. Planck's constant

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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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Which of the following property of air does not increase with rise in temperature?

A. Thermal conductivity

B. Thermal diffusivity

C. Density

D. Dynamic viscosity

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The heat transfer by conduction through a thick cylinder (Q) is given by (where T₁ = Higher temperature, T₂ = Lower temperature, r₁ = Inside radius, r₂ = Outside radius, l = Length of cylinder, and k = Thermal conductivity)

A. Q = [2πlk (T₁ - T₂)]/2.3 log (r₂/r₁)

B. Q = 2.3 log (r₂/r₁)/[2πlk (T₁ - T₂)]

C. Q = [2π (T₁ - T₂)]/2.3 lk log (r₂/r₁)

D. Q = = 2πlk/2.3 (T₁ - T₂) log (r₂/r₁)

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The critical radius is the insulation radius at which the resistance to heat flow is

A. Maximum

B. Minimum

C. Zero

D. None of these

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The energy distribution of an ideal reflector at higher temperatures is largely in the range of

A. Shorter wavelength

B. Longer wavelength

C. Remain same at all wavelengths

D. Wavelength has nothing to do with it

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The ratio of the thickness of thermal boundary layer to the thickness of hydrodynamic boundary layer is equal to (Prandtl number) n, where n is equal to

A. -1/3

B. -2/3

C. 1

D. -1

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Heat conducted through per unit area and unit thick face per unit time when temperature difference between opposite faces is unity, is called

A. Thermal resistance

B. Thermal coefficient

C. Temperature gradient

D. Thermal conductivity

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Film coefficient is defined as the ratio of

A. Thermal conductivity to the equivalent thickness of the film of fluid

B. Temperature drop through the films of fluids to the thickness of film of fluids

C. Thickness of film of fluid to the thermal conductivity

D. Thickness of film of fluid to the temperature drop through the films of fluids

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Stefan Boltzmann law is applicable for heat transfer by

A. Conduction

B. Convection

C. Radiation

D. Conduction and radiation combined

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The process of heat transfer from one particle of the fluid to another by the actual movement of the fluid particles due to difference of density caused by temperature of the particle is known as

A. Conduction

B. Free convection

C. Forced convection

D. Radiation

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Wiens law states that the wave length corresponding to ________ is proportional to the absolute temperature.

A. Minimum energy

B. Maximum energy

C. Both (A) and (B)

D. None of these

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Which of the following statement is correct?

A. A grey body is one which absorbs all radiations incident on it.

B. At thermal equilibrium, the emissivity and absorptivity are same.

C. The energy absorbed by a body to the total energy falling on it, is called emissivity.

D. A perfect body is one which is black in colour.

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The ratio of the emissive power and absorptive power of all bodies is the same and is equal to the emissive power of a perfectly black body. This statement is known as

A. Kirchoffs law

B. Stefan's law

C. Wien' law

D. Planck's law

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The unit of overall coefficient of heat transfer is

A. kcal/m²

B. kcal/hr °C

C. kcal/m² hr °C

D. kcal/m hr °C

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In free convection heat transfer, Nusselt number is function of

A. Grashoff number and Reynold number

B. Grashoff number and Prandtl number

C. Prandtl number and Reynold number

D. Grashoff number, Prandtl number and Reynold number

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In a heat exchanger with one fluid evaporating or condensing, the surface area required is least in

A. Parallel flow

B. Counter flow

C. Cross flow

D. All of these

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When absorptivity (α) = 1, reflectivity (ρ) = 0 and transmissivity (τ) = 0, then the body is said to be a

A. Black body

B. Grey body

C. Opaque body

D. White body

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Accepted Answer

C. Second law of the thermodynamics

Heat transfer takes place as per

Correct Answer :

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Related Questions

A steam pipe is to be lined with two layers of insulating materials of different thermal conductivities. For the minimum heat transfer,

The amount of heat flow through a body by conduction is

Thermal conductivity of glass wool varies from sample to sample because of variation in

If the energy radiated per second per sq. cm. of the surface for wave lengths lying between λ, and λ + dλ is represented by (eλ.dλ), then eλ is called

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

Temperature of steam at around 540°C can be measured by

According to Prevost theory of heat exchange

The logarithmic mean temperature difference (t_m) is given by (where Δt₁ and Δt₂ are temperature differences between the hot and cold fluids at entrance and exit)

Which of the following is expected to have highest thermal conductivity?

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

A non-dimensional number generally associated with natural convection heat transfer is

Joule sec is the unit of

The unit of overall coefficient of heat transfer is

Which of the following property of air does not increase with rise in temperature?

The heat transfer by conduction through a thick cylinder (Q) is given by (where T₁ = Higher temperature, T₂ = Lower temperature, r₁ = Inside radius, r₂ = Outside radius, l = Length of cylinder, and k = Thermal conductivity)

The critical radius is the insulation radius at which the resistance to heat flow is

The energy distribution of an ideal reflector at higher temperatures is largely in the range of

The ratio of the thickness of thermal boundary layer to the thickness of hydrodynamic boundary layer is equal to (Prandtl number) n, where n is equal to

Heat conducted through per unit area and unit thick face per unit time when temperature difference between opposite faces is unity, is called

Film coefficient is defined as the ratio of

Stefan Boltzmann law is applicable for heat transfer by

The process of heat transfer from one particle of the fluid to another by the actual movement of the fluid particles due to difference of density caused by temperature of the particle is known as

Wiens law states that the wave length corresponding to ________ is proportional to the absolute temperature.

Which of the following statement is correct?

The ratio of the emissive power and absorptive power of all bodies is the same and is equal to the emissive power of a perfectly black body. This statement is known as

The unit of overall coefficient of heat transfer is

In free convection heat transfer, Nusselt number is function of

In a heat exchanger with one fluid evaporating or condensing, the surface area required is least in

When absorptivity (α) = 1, reflectivity (ρ) = 0 and transmissivity (τ) = 0, then the body is said to be a

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Heat transfer takes place as per

Correct Answer :

Show all Heat & Mass Transfer MCQ

Related Questions

A steam pipe is to be lined with two layers of insulating materials of different thermal conductivities. For the minimum heat transfer,

The amount of heat flow through a body by conduction is

Thermal conductivity of glass wool varies from sample to sample because of variation in

If the energy radiated per second per sq. cm. of the surface for wave lengths lying between λ, and λ + dλ is represented by (eλ.dλ), then eλ is called

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

Temperature of steam at around 540°C can be measured by

According to Prevost theory of heat exchange

The logarithmic mean temperature difference (tm) is given by (where Δt1 and Δt2 are temperature differences between the hot and cold fluids at entrance and exit)

Which of the following is expected to have highest thermal conductivity?

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

A non-dimensional number generally associated with natural convection heat transfer is

Joule sec is the unit of

The unit of overall coefficient of heat transfer is

Which of the following property of air does not increase with rise in temperature?

The heat transfer by conduction through a thick cylinder (Q) is given by (where T₁ = Higher temperature, T₂ = Lower temperature, r₁ = Inside radius, r₂ = Outside radius, l = Length of cylinder, and k = Thermal conductivity)

The critical radius is the insulation radius at which the resistance to heat flow is

The energy distribution of an ideal reflector at higher temperatures is largely in the range of

The ratio of the thickness of thermal boundary layer to the thickness of hydrodynamic boundary layer is equal to (Prandtl number) n, where n is equal to

Heat conducted through per unit area and unit thick face per unit time when temperature difference between opposite faces is unity, is called

Film coefficient is defined as the ratio of

Stefan Boltzmann law is applicable for heat transfer by

The process of heat transfer from one particle of the fluid to another by the actual movement of the fluid particles due to difference of density caused by temperature of the particle is known as

Wiens law states that the wave length corresponding to ________ is proportional to the absolute temperature.

Which of the following statement is correct?

The ratio of the emissive power and absorptive power of all bodies is the same and is equal to the emissive power of a perfectly black body. This statement is known as

The unit of overall coefficient of heat transfer is

In free convection heat transfer, Nusselt number is function of

In a heat exchanger with one fluid evaporating or condensing, the surface area required is least in

When absorptivity (α) = 1, reflectivity (ρ) = 0 and transmissivity (τ) = 0, then the body is said to be a

Also checkout

The logarithmic mean temperature difference (t_m) is given by (where Δt₁ and Δt₂ are temperature differences between the hot and cold fluids at entrance and exit)