Final answer:
The correct answer to the question regarding the yield strength of an alloy based on grain diameter alone is 'Not enough information provided'. Yield strength is determined by multiple factors, including the type of alloy, its microstructure, and additional material properties that are not given in the question.
Step-by-step explanation:
The question, What is the yield strength of an alloy with an average grain diameter of 5x10⁻²? falls under the category of Engineering, specifically material science. The yield strength of an alloy is an important mechanical property determined by various factors, including its chemical composition, heat treatment, and microstructure.
In this scenario, the provided information about the average grain diameter alone is insufficient to determine the yield strength of an alloy. The yield strength is not only dependent on grain size but also on the specific type of alloy, its processing, and the presence of any impurities or alloying elements. Therefore, the correct answer to the student's question is 4) Not enough information provided.
To accurately determine the yield strength, detailed material properties and perhaps results from standardized testing like tensile tests would be required. Without additional context or material specifics, the yield strength cannot be calculated or inferred from grain size alone.