An electric device delivers a current of [tex]$15.0 A$[/tex] for 30 seconds. How many electrons flow through it?
Answer (2)
The problem involves analyzing temperature data to determine which conclusion about the absorbent and reflective properties of materials is best supported. By comparing the temperatures of the materials, we can infer their relative absorbent and reflective properties. The analysis shows that:
Higher temperature indicates greater absorption.
Lower temperature indicates greater reflection.
Material W is less absorbent than material Z.
Therefore, the best supported conclusion is that Material W is less absorbent than material Z. M a t er ia l Wi s l ess ab sor b e n tt hanma t er ia lZ .
Explanation
Understanding the Problem Anya recorded the temperatures of four different smooth materials (W, X, Y, Z) after they were placed under a heat lamp for thirty minutes. The temperatures are: W = 87°F, X = 99°F, Y = 75°F, Z = 105°F. The question asks which conclusion is best supported by the information in the chart. We need to determine which of the given conclusions is best supported by the temperature data.
Analyzing the Conclusions Let's analyze each conclusion based on the temperature data. We assume that higher temperature implies more absorption and less reflection.
Analyzing Conclusion 1 Conclusion 1: Material W is less absorbent than material Z. Since Z (105°F) > W (87°F), this statement is supported.
Analyzing Conclusion 2 Conclusion 2: Material Y is the least reflective. Since Y has the lowest temperature (75°F), it would be the most reflective, not the least. This statement is not supported.
Analyzing Conclusion 3 Conclusion 3: Material X is more reflective than material W. Since X (99°F) > W (87°F), X is less reflective than W. This statement is not supported.
Analyzing Conclusion 4 Conclusion 4: Material Z is the least absorbent. Since Z has the highest temperature (105°F), it would be the most absorbent, not the least. This statement is not supported.
Final Answer Comparing the analysis of each conclusion, the first conclusion is best supported by the data.
Examples
Understanding how different materials absorb heat is crucial in designing energy-efficient buildings. For example, choosing roofing materials that absorb less heat can significantly reduce cooling costs in the summer. Similarly, in solar panel technology, selecting materials that efficiently absorb sunlight is essential for maximizing energy production. This problem demonstrates a simplified version of the considerations engineers and scientists make when selecting materials for various applications based on their thermal properties.
The current of 15.0 A flowing for 30 seconds results in a total charge of 450 C. This charge corresponds to approximately 2.81 x 10^21 electrons flowing through the device. The calculation involves using the relationship between current, time, and charge, then converting the charge to the number of electrons using the charge of a single electron.
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