Question

Arrange the following materials in the ascending order of their electrical conductivities.
A. Rubber
B. Iron
C. Carbon
D. Copper
Choose the correct answer from the options given below:

• A. A, B, C, D
• B. D, B, C, A
• C. A, C, B, D
• D. C, A, B, D

Hint:

Insulator, then carbon, then iron, then copper.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
We need to rank four materials from the poorest to the best conductor of electricity.

Step 2: Rubber:
Rubber is an insulator. Its conductivity is about \(10^{-13}\) S/m or even lower, so it is the lowest of the four.

Step 3: Carbon:
Carbon (graphite) conducts poorly compared with metals. Its conductivity is about \(10^{4}\) S/m, which is much above rubber but far below metals.

Step 4: Iron:
Iron is a metal with conductivity of about \(10^{7}\) S/m. It is higher than carbon.

Step 5: Copper:
Copper has one of the highest conductivities among common metals, about \(6\times10^{7}\) S/m. It is higher than iron.

Step 6: Arrange in ascending order:
The order is Rubber < Carbon < Iron < Copper, that is A, C, B, D. This is option 3. Option 1 puts iron before carbon. Option 2 is the descending-type order. Option 4 puts carbon before rubber.

Final Answer:
The ascending order of conductivity is A, C, B, D, which is option 3. \[ \boxed{\text{Option 3: A, C, B, D}} \]