{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

EEE224_Fall10_MaterialMedia

# EEE224_Fall10_MaterialMedia - METU NCC EEE 224...

This preview shows pages 1–9. Sign up to view the full content.

1 EEE 224 ELECTROMAGNETIC THEORY Static Electric Field in Material Media METU - NCC Assist. Prof. Dr. Özlem Özgün Office : S-144 Phone : 661 2972 E-mail : [email protected] Web : http://www.metu.edu.tr/~ozozgun/

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
2 What about electrostatic fields in a material media ? So far, we considered electrostatic fields in free space (or vacuum). Material Media Material classification: Conductors Dielectrics (or insulators) Semiconductors (in between the two)
3 Material Media (a) The conductor exhibits no energy gap between the valence and conduction bands. (b) The insulator shows a large energy gap. (c) The semiconductor has only a small energy gap.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
4 σ : conductivity (Siemens/m) If σ >> 1, good conductor (e.g., metals) Charges flow easily. If σ << 1, good insulator Almost no charge flows.
5 Static Electric Fields in Conductors FACT 1 : In electrostatics, electric field E=0 inside conductors . E e : Electric field before the conductor was introduced. E i : Electric field created inside the conductor as a reaction to E e . E : Resultant electric field after the transient period following the insertion of conduction object. E i = -E e Î E = E i + E e = 0 inside the conductor

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
6 Static Electric Fields in Conductors FACT 2 : Electric field E is always perpendicular (normal) to the surface of a conductor . (Its tangential component is zero) 0 E ∇× = 0 C Ed l = v 0 (as h Î 0) 0 (as h Î 0) 0 (as E=0)
7 Static Electric Fields in Conductors FACT 3 : The normal component of E-field is: 0 enclosed S Q Ed s ε ⋅= v 0 enclosed top bottom sides Q ++ = ∫∫ ρ s : surface charge density 0 (as h Î 0) 0 (as E=0) 0 s n s Es ρ Δ Δ= 0 s n E = 0 s n E =

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
8 Static Electric Fields in Conductors FACT 4 : The conductor is an equipotential surface.
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 23

EEE224_Fall10_MaterialMedia - METU NCC EEE 224...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online