Question

The material which has a resistivity value of about 10x10¹⁰ Ω-m at 20 °C is

• A. Air
• B. Glass
• C. Rubber
• D. Iron

Answer 1

The Correct Option is B

Step 1: Recall the resistivity values of common materials.

• Air: Air is an insulator and has a very high resistivity, typically on the order of \( 10^{13} \, \Omega\text{-m} \) to \( 10^{16} \, \Omega\text{-m} \). This is much higher than \( 10 \times 10^{10} \, \Omega\text{-m} \).
• Glass: Glass is also an insulator and has a resistivity in the range of \( 10^{10} \, \Omega\text{-m} \) to \( 10^{14} \, \Omega\text{-m} \). A value of \( 10 \times 10^{10} \, \Omega\text{-m} \) falls within this range.
• Rubber: Rubber is another insulator with resistivity values typically ranging from \( 10^{13} \, \Omega\text{-m} \) to \( 10^{16} \, \Omega\text{-m} \), which is higher than \( 10 \times 10^{10} \, \Omega\text{-m} \).
• Iron: Iron is a conductor and has a very low resistivity, approximately \( 10^{-7} \, \Omega\text{-m} \), which is far lower than \( 10 \times 10^{10} \, \Omega\text{-m} \).

Step 2: Match the resistivity value to the correct material.

The resistivity value \( 10 \times 10^{10} \, \Omega\text{-m} \) corresponds to glass, as it falls within the typical resistivity range for glass.

Final Answer: The material is \( \mathbf{\text{Glass}} \), which corresponds to option \( \mathbf{(2)} \).