Question

Copper and silicon material is cooled down from \(600 \mathrm{~K}\) to $400 \mathrm{~K}$ then, resistivity of cooper and silicon (A) increases, decreases (B) decreases, increases (C) decreases, decreases (D) increase, increases

Short answer

When the temperature of copper (a metal) and silicon (a semiconductor) decreases from 600 K to 400 K, the resistivity of copper decreases while the resistivity of silicon increases. Therefore, the correct answer is \( \textbf{(B) decreases, increases} \).

Step-by-step solution

Understand the properties of copper and silicon

Copper is a metal, which means it follows the properties of metallic conductors. In metallic conductors, the resistivity increases with an increase in temperature. Conversely, when the temperature decreases, the resistivity decreases. Silicon, on the other hand, is a semiconductor material. In semiconductors, the resistivity decreases with an increase in temperature. This means that when the temperature decreases, the resistivity increases.

Apply the properties to the given temperature change

As the temperature decreases from 600 K to 400 K, we can apply the properties of each material to understand how their resistivity would change: 1. Copper: As a metal, its resistivity would decrease with the decrease in temperature. 2. Silicon: As a semiconductor, its resistivity would increase with the decrease in temperature.

Match the results with the answer choices

Based on our understanding from steps 1 and 2: - Copper's resistivity decreases - Silicon's resistivity increases Comparing these results with the given answer choices, we find that the correct answer is (B) decreases, increases.