ELECTRIC-FLUX Problems and solutios.pptx

Electron flux

1. Electric field inside a conductor Faraday demonstrated that the electric field is zero inside a closed conducting surface and that an excess charge placed on a solid conductor resides entirely on its surface.

2. Electric field inside a conductor He constructed a room covered with metal foil inside. This room, with a conducting frame that protected Faraday from static charge is known as Faraday cage.

3. ELECTRIC FLUX ELECTRIC FLUX The word flux comes from the Latin word fluxus meaning “flow”. Electric flux ( ɸ) is a measure of the number of field lines passing through a surface.

4. ELECTRIC FLUX ELECTRIC FLUX Mathematically: E-electric field A-area vector Direction of area vector is same as the vector perpendicular to the area  

5. ELECTRIC FLUX ELECTRIC FLUX

6. SAMPLE PROBLEM 3 A flat surface of area 1.25 is rotated through a uniform horizontal electric field of 5 N/C. What is the electric flux if the surface is (a) parallel and (b) perpendicular to the field?  

7. Carl Friedrich Gauss , a German scientist, formulated a law, which relates electric field, electric flux, and electric charge. GAUSS’S LAW

8. The total electric flux through a surface is the total electric charge ( ) inside the surface divided by - permittivity of of free space ( )   GAUSS’S LAW

9. In symbols,   GAUSS’S LAW

10. Calculate the total electric flux ɸ for each of the closed surfaces a,b,c , and d as shown. Note that q1=+3C, q2=+1C, q3=-5C, and q4=-9C. SAMPLE PROBLEM 4

11. Gauss’s Law can be used to compute the electric field due to a system of point charges as well as for a continuous charge distribution. Charge distribution and gauss’s law

12. Charge distribution must be uniform and symmetrical. The charge distribution may be expressed in terms of linear charge density, surface charge density, or volume charge density. Charge distribution and gauss’s law

13. Linear charge density ʎ is charge per unit length, surface charge density is charge per surface area, and volume charge density is charge per unit volume of a body.   ʎ, ,  

14. If a solid insulating sphere of radius 50.0 cm carries a total charge of 150 nC uniformly distributed throughout its volume what is its (a) volume charge density? What is the magnitude of the electric field at (b) 10 cm and (c) 65 cm from the center of the sphere. SAMPLE PROBLEM 5

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