Question

The number of free electrons per unit volume is more in

• A. glass
• B. graphite
• C. iron
• D. pure water

Answer 1

The correct option is C

iron

The explanation for the correct solution :

Option C:

1. Iron is a conductor it has free electrons on its surface as compared to glass, graphite, and water and it conducts electricity.
2. So, the number of free electrons per unit volume is more in iron.

The explanation for the incorrect solution:

Option A:

Glass is an insulator and it does not conduct electricity. So, it does not have free electrons on its surface.

Option B:

Graphite is an insulator they do not conduct electricity and hence does not have free electrons on its surface.

Option D:

Pure Water is an insulator and does not conduct electricity. So, there also have no free electrons on its surface.

Thus, option (C) is correct.