Si and Cu are cooled to a temperature of 300 K,thenresistivity? [2001]...
Conductivity of semiconductor increases
with increase in temperature while
conductivity of metal decreases with
increase in temperature.
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Si and Cu are cooled to a temperature of 300 K,thenresistivity? [2001]...
Here answer is wrong it should be option à you can check it in text book
Si and Cu are cooled to a temperature of 300 K,thenresistivity? [2001]...
**Answer:**
To understand why the resistivity of Si (Silicon) increases and the resistivity of Cu (Copper) decreases when cooled to a temperature of 300 K, we need to consider the behavior of these materials at different temperatures.
**Effect of Temperature on Resistivity:**
The resistivity of a material is a measure of its opposition to the flow of electric current. It is directly influenced by the temperature of the material. The relationship between resistivity and temperature can be understood using the following equation:
ρ = ρ₀(1 + α(T - T₀))
Where:
- ρ is the resistivity of the material at a given temperature,
- ρ₀ is the resistivity of the material at a reference temperature (usually room temperature),
- α is the temperature coefficient of resistivity, and
- T and T₀ are the temperatures at which resistivity is being measured and the reference temperature, respectively.
**Effect on Si (Silicon):**
Silicon is a semiconductor material with a negative temperature coefficient of resistivity. This means that as the temperature increases, the resistivity of silicon decreases. Conversely, when the temperature decreases, the resistivity of silicon increases. Therefore, when silicon is cooled to a temperature of 300 K, its resistivity will increase compared to its resistivity at higher temperatures.
**Effect on Cu (Copper):**
Copper is a metal with a positive temperature coefficient of resistivity. This means that as the temperature increases, the resistivity of copper also increases. When copper is cooled to a temperature of 300 K, its resistivity will decrease compared to its resistivity at higher temperatures.
**Conclusion:**
Based on the above explanations, we can conclude that when Si and Cu are cooled to a temperature of 300 K:
- The resistivity of Si (Silicon) increases.
- The resistivity of Cu (Copper) decreases.
Therefore, the correct answer is option 'A': For Si increases and for Cu decreases.