Fundamentals of Electricity

Fundamentals of Electricity

I. Definition of Terms

• Charge - Fundamental physical quantity responsible for electrical phenomena.

• Unit: Coulomb (C)

  • Positive charge (proton): $1.6 imes 10^{-19} ext{ C}$

  • Negative charge (electron): $-1.6 imes 10^{-19} ext{ C}$

• Ways of Charging:

  1. Rubbing

  2. Conduction

  3. Induction

• Net Charge

  • Definition: Sum of all positive and negative charges in the object.

• Triboelectric Series

  • Definition: List of materials with a greater tendency to become positive (+) or negative (−).

  • Purpose: Helps determine which material combinations create the most static electricity.

• Law of Conservation of Charge

  • Statement: If a system starts with equal charge distributions, the system will be in a state of equilibrium unless a charge is added or removed from the system.

  • Origin: Benjamin Franklin

• Coulomb’s Law

  • Definition: Electric force is determined by the product of two charge values multiplied by a proportionality constant and divided by the square of the distance between the charges.

  • Formula:
    $F<em>e = k rac{q</em>1 q_2}{r^2}$

  • Where:

  • $F_e$ = electric force

  • $k$ = Coulomb’s Constant = $9 imes 10^{9} rac{N imes m^2}{C^2}$

  • $q<em>1, q</em>2$ = charges

  • $r$ = distance between charges

• Electric Field

  • Definition: A field existing in a region around a charged particle.

  • Formula:
    $E = k rac{q}{r^2}$

• Gauss’ Law

  • Definition: Relation between the electric field at all points on a closed surface and the total charge enclosed within the surface.

  • Gaussian Surface: A hypothetical surface immersed in an electric field that may or may not enclose a charge.

• Electric Flux

  • Definition: Strength of an electric field over an area in a field region.

II. FORMULAE

• Quantization of Charge

  • Formula:
    $q = n c$

  • Where:

  • $n$ = Amount of charges present

  • $c$ = Charged particle present

• Electric Force

  • Formula:
    $F<em>e = k rac{q</em>1 q_2}{r^2}$

• Electric Field

  • Formula:
    $E = k rac{q}{r^2}$

• Electric Flux

  • Formula:
    $ext{ } <br>\Phi_E = EA \, ext{cos} heta$

  • Where:

  • $A$ = Area of the region

  • $heta$ = Angle of the surface

• Gauss’ Law (general)

  • Formula:
    $ext{ } <br>\Phi = rac{1}{ ext{}} \sum ext{q}_{enc} <br>$

• Gauss’ Law (spherical shell)

  • Formula:
    $ext{ } \Phi = rac{q}{ ext{}} <br>$

• Gauss’ Law (solid sphere)

  • For outside surface, use spherical shell equation.

  • For inside the sphere, the formula is:
    $ext{ } \Phi = rac{q r^3}{ ext{}} <br>$

  • Where:

  • $r$ = minor internal radius of the sphere

  • $R$ = major internal radius of the sphere

References

• Bauer, W., & Westfall, G. D. (2016). General physics 2 (2nd ed.). Quezon City: Abiva Publishing House, Inc.

• Bautista, D.C. (2013). Science impact: Integrated science (3rd ed.). Antipolo City: Academe Publishing House, Inc.

• Cacanindin, D.D.A. et al. (2016). General physics 2. Quezon City, Vibal Publishing House, Inc.

• Catchilar, G. C. & Malenab, R. G., (2003). Fundamentals of physics. Mandaluyong City, National Book Store.

• Cordero-Navaza, D. & Valdez, B. J., (2006). Physics IV (2nd ed.). Quezon City, Phoenix Publishing House, Inc.

• Freedman, R. A., Ford, A. L., & Young, H. D. (2011). Sears and Zemansky's university physics (with modern physics) (13th ed.). Addison-Wesley.

• Giambattista, A., Richardson, B. M., Richardson, R. C. (2007). College physics (2nd ed.). New York: The McGraw-Hill Companies, Inc.

• Halliday, D., Resnick, R. & Walker, J., (2007). Fundamentals of physics (5th ed.). New York: John Wiley and Sons, Inc.

• Hewitt, Paul G., (2007), Conceptual physics (3rd ed.). California: Addison-Wesley Publishing Company.

• Santiago, K. S., & Silverio, A. A. (2016). Exploring life through science: Senior high school physical science. Quezon City: Phoenix Publishing House, Inc.

• Wilson, Jerry D. & Buffa, Anthony J., (2003). Physics (4th ed.). Prentice Hall.