One of the reasons for insulating the pipes is:

The rate of radiant energy, that is emitted by a surface at any temperature and in small wavelengths is found from the known rate of energy, that under the same conditions will be emitted from a black surface, by multiplying with the absorptivity. The above enunciation is called:

Which of the following is generally used to measure the temperature inside the furnace?

All heat transfer processes, except:

What is thermal deffusivity?

Which of the following is a unit of thermal deffusity?

Non-Isotropic conductivity is shown by which of the following?

For glass wool thermal conductivity changes from sample to sample due changes in:

Which of the following is the S.I. unit of thermal conductivity?

What is the value of the Prand’l number of air?

____ is the movement of heat from one body to another by means of conduction, convection, or radiation.

____ is a mode of heat transfer in which heat is transferred by molecular interaction through bodies in contact.

____ is a mode of heat transfer in which heat is transferred due to the mixing and motion of particles of a substance.

____ is a mode of heat transfer in which heat is transferred between two bodies by energy propagating electromagnetic waves.

The substance moves because of the decrease in its density which is caused by increase in temperature

The substance moves because of the application of mechanical power such as that of a fan.

____ is any device which affects the transfer of heat from one substance to another

Heat Exchagers wherein a fluid at a constant temperature gives up heat to a colder fluid the temperature of which gradually increases as it flows through the device. The heating fluid can be at rest or moving in any direction. An example of this type would be a _____?

Devices wherein a fluid at constant temperature receives heat from a warmer fluid the temperature of which decreases as it flows through the exchager. The heated fluid can be at rest or moving in any direction. An example of this type is _____?

____ heat exchangers wherein fluids dlow in the same direction and both of them change their temperature. An example of this type are water heater, oil heater and coolers

____ heat exhangers wherein the fluids flow in directions opposite to one another. This possibly the most favorable kind of fluid heaters and coolers.

____ is a body that absorbs all elwctromagnetic radiation. It absorbs all wavelenght such no reflection occurs.

____ is the mode of heat transfer through electromagnetic wave. Anything whose temperature is above the surrounding will always radiate of significant amount.

All substances emit radiation, the quantify and quality of which depends upon the absolute temperature and the properties of the material, composing the radiating body.

For bodies in thermal equilibrium with their environment, the ratio of total emissive power to the absorptivity is constant at any temperature

The total energy emitted by a black body is proportional to the fourth power to the absolute temperature of the body.

____ is the mechanism of heat transfer whereby heat energy is transferred by moving fluids

____ is a dimensionless number which is significant in the design of a model of any system in which the effect of viscosity is important in controlling the velocities or the flow pattern of a fluid; equal to the product of density, of velocity and charactristics length divided by the fluid viscosity.

____ is a dimensionless number used in the study of forced and free convection, equal to the dynamic viscosity times the specific heat at constant pressure divided by the thermal conductivity.

____ is the dimensionless number used in the study of forced convection which gives a measure of the ratio of the total heat transfer to conductive heat transfer, and is equal to the heat transfer coeffificient times the characteristics length divided by the thermal conductivity.

____ is a dimentionless number used in the study of the free convection of a fluid caused by a hot body. It is equal to the product of the fluids coefficient of thermal expansion, the temperature difference between the hot body and the fluid, the cube of a typical dimension of the body and the square of the fluids density divided by the square of the fluid’s dynamic viscosity.

According to Prevost theory of heat exchange

Thermal conductivity of wood depends on which of the following?

A fur coat on an animal will help the animal to remain:

The nature of the flow of a fluid inside a tube, whether it is turbulent or laminar, can be ascertained by:

By which of the following modes of heat transfer is the Stefan-Boltzmann law applicable?

At all wave lengths and temperatures the monochromic emissivity of a white body is equal to?

The radiation from flames is having

The statement that the emissivity and absorptivity of a surface is surrounded by its own temperature are the same for both monochromic and total radiation is called: