# Principles of Technology

## Thermal Resistance (4:4)

### Vocabulary (pages 95-104)

Thermal resistance is opposition to _______________________________________________________."

"Low thermal resistance allows _______________________________________________________."

High thermal resistance results in _______________________________________________________."

What is the formula for thermal resistance.

Re-arrange to solve for all variables.

What are the SI and English units of thermal resistance?

Think

Thermal conductivity

What is the formula relating thermal resistance to thermal conductivity?

Re-arrange to solve for all variables.

R-factor

Insulator

Molecular vibration

Re-work "Example 4-I" (pg. 97) using the following values: "The temperature inside a house is 68 deg. F when the outside temperature is -11 deg. F. A furnace supplies 2437 BTU/hr to maintain the inside temperature at 68 deg. F." Show all formulas, steps, and work.

Re-work "Example 4-J" (pg. 101) using the following values: A=6 ft2; l = .25"; and T=40F deg. Show all formulas, steps, and work.