Number of electrons per unit volume

In summary, the number of electrons per unit volume, n, is fixed in a conductor regardless of temperature because the number of free/conduction electrons is at saturation and heating the material does not produce any more. In contrast, in semiconductors, electrons can be promoted to the conduction band by thermal energy, but the total number of electrons in the material remains unaffected. Additionally, in any material, there are both free electrons that can participate in conduction and bound electrons that cannot.
  • #1
thereddevils
438
0
Why is the number of electrons per unit volume , n fixed in a conductor regardless of the temperature while its not in semiconductors ??
 
Physics news on Phys.org
  • #2
I think you mean number of free/conduction electrons.
In a semiconductor, electrons can promoted to the conduction band by thermal energy; i.e. by raising the temperature of the material. In a conductor, the number of free/conduction electrons is more or less at saturation, and heating the material does not produce any more.

Of course the total number of electrons in the material is not affected by temperature.
 
  • #3
Stonebridge said:
I think you mean number of free/conduction electrons.
In a semiconductor, electrons can promoted to the conduction band by thermal energy; i.e. by raising the temperature of the material. In a conductor, the number of free/conduction electrons is more or less at saturation, and heating the material does not produce any more.

Of course the total number of electrons in the material is not affected by temperature.

thanks so free electrons and electrons are different ? I thought they are the same .
 
  • #4
They are only "different" in that in any material some are free to take part in conduction and others are not.
Some are situated deep in the lower energy levels of the atom where they are strongly bound, while others are in the outer levels where they are weakly bound.
 

1. How is the number of electrons per unit volume calculated?

The number of electrons per unit volume is calculated by dividing the total number of electrons in a given volume by the volume itself.

2. What is the unit of measurement for number of electrons per unit volume?

The unit of measurement for number of electrons per unit volume is typically expressed as electrons per cubic meter (e/m³) or electrons per cubic centimeter (e/cm³).

3. How does the number of electrons per unit volume change in different materials?

The number of electrons per unit volume can vary depending on the type of material. Metals, for example, tend to have a higher number of electrons per unit volume compared to insulators.

4. Can the number of electrons per unit volume be manipulated?

Yes, the number of electrons per unit volume can be manipulated through various methods such as applying an electric field or changing the temperature of the material.

5. What is the significance of the number of electrons per unit volume in electronic devices?

The number of electrons per unit volume plays a crucial role in the conductivity and overall performance of electronic devices. It helps determine the flow of electric current and the behavior of materials in different electronic components.

Similar threads

  • Introductory Physics Homework Help
Replies
12
Views
1K
  • Introductory Physics Homework Help
Replies
1
Views
555
  • Introductory Physics Homework Help
Replies
4
Views
704
  • Introductory Physics Homework Help
Replies
2
Views
2K
  • Introductory Physics Homework Help
Replies
3
Views
2K
  • Introductory Physics Homework Help
Replies
5
Views
976
  • Introductory Physics Homework Help
Replies
8
Views
976
  • Introductory Physics Homework Help
Replies
32
Views
1K
  • Introductory Physics Homework Help
2
Replies
35
Views
1K
  • Introductory Physics Homework Help
Replies
9
Views
2K
Back
Top