Question

The INCORRECT statement is

• A. Resistivity copper increases with increase of temperature
• B. Resistivity of germanium decreases with the increases of temperature
• C. Resistivity of semiconductors is higher than that of the conductors
• D. Resistive of nichrome shows a weak dependence with temperature
• E. Resistivity of insulators is independent of temperature

Answer 1

Answer: (E)

The resistivity of insulators is not independent of temperature. In fact, for insulators, the resistivity decreases with increasing temperature, though it is much more sensitive than in conductors. The resistivity of conductors increases with temperature, whereas in semiconductors and insulators, it decreases as more charge carriers are available at higher temperatures. Thus, the incorrect statement is, as resistivity of insulators is not independent of temperature.

The correct option is (E) : Resistivity of insulators is independent of temperature

Answer 2

Let's examine each statement to find the incorrect one:  

1. Resistivity of copper increases with temperature
✔️ True – For conductors like copper, resistivity increases with temperature. 

2. Resistivity of germanium decreases with temperature
✔️ True – Germanium is a semiconductor, and its resistivity decreases as temperature increases. 

3. Resistivity of semiconductors is higher than that of conductors
✔️ True – Semiconductors have higher resistivity than metals but lower than insulators. 

4. Resistivity of nichrome shows a weak dependence on temperature
✔️ True – Nichrome is used in heating elements due to its low temperature coefficient of resistivity. 

5. Resistivity of insulators is independent of temperature
❌ Incorrect – Resistivity of insulators does depend on temperature; it usually decreases as temperature increases. 

Final Answer: \( \boxed{\text{Resistivity of insulators is independent of temperature}} \)