UNIT 4 Black Body Radiation

Which of the following statements about blackbody radiation is true?

• a) It is the maximum possible amount of radiation that can be emitted at a given temperature.
• b) It only occurs at high temperatures.
• c) It only occurs in a vacuum.
• d) It is a type of convection.

Which of the following is true about the Stefan-Boltzmann law?

• a) It relates the wavelength of maximum emission to the temperature of the blackbody.
• b) It relates the total energy emitted to the fourth power of the temperature of the blackbody.
• c) It relates the rate of energy emission to the temperature of the blackbody.
• d) It relates the energy emitted at a given wavelength to the temperature of the blackbody.

Which of the following is a dimensionless quantity used in radiation heat transfer?

• a) Stefan-Boltzmann constant
• b) Wien's displacement law constant
• c) Emissivity
• d) Shape factor

What is the emissivity of a perfect blackbody?

• a) 0
• b) 1
• c) 0.5
• d) it depends on the temperature of the blackbody

Which of the following is NOT a method to reduce radiation heat transfer between two surfaces?

• a) Using radiation shields
• b) Changing the surface material of the objects
• c) Increasing the distance between the objects
• d) Painting the surface with a high emissivity coating

How does the electrical analogy help to solve radiation heat transfer problems?

• a) By representing radiation heat transfer as a current flow
• b) By using Ohm's law to calculate the rate of heat transfer
• c) By using the electrical conductivity of materials to calculate the heat transfer coefficient
• d) By using Kirchhoff's law to calculate the radiation exchange between two surfaces