### Related Questions

What is the correct answer?

4

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

What is the correct answer?

4

# The concept of overall coefficient of heat transfer is used in heat transfer problems of

D. Conduction and convection

What is the correct answer?

4

# The transfer of heat by molecular collision is known as

What is the correct answer?

4

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

What is the correct answer?

4

# Thermal conductivity of air with rise in temperature

D. May increase or decrease depending on temperature

What is the correct answer?

4

# The highest thermal diffusivity is of

What is the correct answer?

4

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

What is the correct answer?

4

# The amount of radiation mainly depends on

C. Type of surface of body

What is the correct answer?

4

# According to Stefan Boltzmann law, the total radiation from a black body per second per unit area is directly proportional to the

B. Square of the absolute temperature

C. Cube of the absolute temperature

D. Fourth power of the absolute temperature

What is the correct answer?

4

# Joule sec is the unit of

A. Universal gas constant

What is the correct answer?

4

# A cube at high temperature is immersed in a constant temperature bath. It loses heat from its top, bottom and side surfaces with heat transfer coefficients of h₁, h₂ and h₃ respectively. The average heat transfer coefficient for the cube is

What is the correct answer?

4

# Thermal diffusivity is

A. A dimensionless parameter

B. Function of temperature

C. Used as mathematical model

D. A physical property of the material

What is the correct answer?

4

# The unit of overall coefficient of heat transfer is

What is the correct answer?

4

# Two balls of same material and finish have their diameters in the ratio of 2: 1 and both are heated to same temperature and allowed to cool by radiation. Rate of cooling by big ball as compared to smaller one will be in the ratio of

What is the correct answer?

4

# Conduction is a process of heat transfer

A. From one particle of the body to another without the actual motion of the particles

B. From one particle of the body to another by the actual motion of the heated particles

C. From a hot body to a cold body, in a straight line, without affecting the intervening medium

What is the correct answer?

4

# The total radiation from a black body per second per unit area is ________ fourth power of the absolute temperature. This statement is known as Stefan Boltzmann law.

B. Directly proportional to

C. Inversely proportional to

What is the correct answer?

4

# 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

D. Conduction and convection

What is the correct answer?

4

# According to Wien's law, the wavelength corresponding to maximum energy is proportion to

A. Absolute temperature (T)

What is the correct answer?

4

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

B. Provide support for tubes

C. Prevent stagnation of shell side fluid

What is the correct answer?

4

# 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

What is the correct answer?

4

# The value of Prandtl number for air is about

What is the correct answer?

4

# The amount of radiation mainly depends upon the

B. Temperature of the body

C. Type of surface of the body

What is the correct answer?

4

# 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.

What is the correct answer?

4

# Planck's law holds good for

What is the correct answer?

4

# The unit of Stefan Boltzmann constant is

What is the correct answer?

4

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

What is the correct answer?

4

# 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

What is the correct answer?

4

# Heat transfer by radiation mainly depends upon

C. Kind and extent of its surface

What is the correct answer?

4

# The use of heat exchangers is made in

A. Radiators in automobile

B. Condensers and boilers in steam plants

C. Condensers and evaporators in refrigeration and air conditioning units

What is the correct answer?

4

# According to Stefan's law, the total radiation from a black body per second per unit area is proportional to