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What is meant by the U-value of a material? - Leaving Cert Physics - Question 5(i) - 2014
Question 5(i)
What is meant by the U-value of a material?
Worked Solution & Example Answer:What is meant by the U-value of a material? - Leaving Cert Physics - Question 5(i) - 2014
Step 1
Definition of U-value
Answer
The U-value of a material is defined as the measure of the rate of heat transfer through one square meter of the material for each degree of temperature difference between its two sides. Mathematically, it quantifies the amount of heat (in watts) that flows through the material when there is a temperature difference of one degree Celsius between the two surfaces.
Step 2
Understanding the Measurement
Answer
The U-value is expressed in watts per square meter Kelvin (W/m²·K). A lower U-value indicates a better insulating material, which means less heat is lost through the material. Therefore, materials with low U-values are preferred in construction for better energy efficiency.