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Lesson: Thermal Conduction

Worksheet • 18 Questions

Q1:

A large animal has a 1.40 m2 surface area. The animal’s surface is covered with 3.00-cm-thickness fur that has a thermal conductivity of . The animal’s skin is at a temperature of and the air temperature around the animal is .

What is the rate of heat conduction through the fur?

What daily intake of energy from food will the animal need to replace energy lost by heat conduction?

Q2:

An astronaut is performing an extravehicular activity while shaded from sunlight. The astronaut is wearing a spacesuit that can be modeled as perfectly white, with an emissivity of exactly 0. However, one part of the spacesuit, a rectangular patch with side lengths of 2 cm and 4 cm, is not white. The patch has an emissivity 0.220. The spacesuit under the patch is 0.720 cm thick, with a thermal conductivity of 0 . 0 4 0 / W m C , and its inner surface is at a temperature of 2 2 C . Assume the patch is so thin that its outer surface is at the same temperature as the outer surface of the spacesuit under it. Determine the temperature of the patch. Use a value of 3 K for the temperature of space around the astronaut.

Q3:

The total surface area of a house is 300 m2. The average thickness of the house walls is 0.10 m and their thermal conductivity is 5 . 0 × 1 0 4 kW/m⋅K. How much energy must be supplied to the house in a day to keep its interior temperature 1 0 C higher than the temperature outside.

  • A 1 . 3 × 1 0 9 J
  • B 3 . 0 × 1 0 6 J
  • C 0 . 3 0 × 1 0 6 J
  • D 2 . 3 × 1 0 9 J
  • E 5 . 3 × 1 0 6 J
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