PHYSICS 2 QUARTER 1

Electrostatics

study of stationary electric charges

Characteristics of Electrically Charged Objects

-unlike charges attract

-like charges repel

-charge is conserved

ELECTRIC CHARGE

-fundamental property of subatomic particles that gives rise to the phenomenon of experiencing force in the presence of electric and magnetic fields.

-positive and negative

ELECTRIC CHARGE FORMULA

Q=ne

COULOMB’S LAW

-measures the magnitude of the electrostatic force (F) between two charges

Formula for Coulomb’s Law

F=kq1q2/r²

Charging by Conduction

- when a charge object touches a neutral object allowing electrons to transfer

-after contact, both objects share the same type of charge

-physical contact is required

-only works in conductors

Charging by Induction

-a method of charging an object without touching another charged object

-involves movement of electrons due to the influence of a nearby charged object

-only works in conductors

TRIBOELECTRIC CHARGING

-often through friction

- through rubbing, electrons transfer from one material to another. Causing one to be negatively charged and one positively charged.

ELECTRIC FIELD

-an electric property associated with each point in space with charge is present in any form. (Electric force exerted per unit charge)

Electric Field Formula

E = F/Q

Electric Field Formula with k

E= kq/r²

ELECTRIC FLUX

Total Number of Elecric Field Lines penetrating a surface proportional to the product of E and A

Electric flux surface perpendicular to the e field lines

EA

Electric flux surface not perpendicular to the e field lines

EA cos theta

Electric Flux surface parallel to the e field lines

Flux is 0

Closed Surface

a surface that divides space into an inside and outside region where one cannot move from one region to the other without crossing the surface

GAUSS’S LAW

states that the total electric flux through any closed surface is proportional to the total net electric charge inside the surface

Gauss Law formula

q/permittivity of free space

9×10^9 Nm²/C²

k

electrostatic constant

8.85 × 10^-12 C/Nm²

ε sub zero

permittivity of free space

ELECTRIC POTENTIAL

-the electric potential energy per unit of charge at a specific point in an electric field

- measured in volts

VOLTAGE

-also called electric potential difference

- difference in electric potential between two points

Voltage Formula

V=ΔU/q

Voltage formula with k

V= kq/r

ELECTRIC POTENTIAL ENERGY

-total energy in a system of charges due to their position in an electric field.

Electric Potential Energy Formula

U=kq1q2/r

Change in Electric Potential Energy

ΔU=-q E d

ELECTRIC CURRENT

-when charges move

-it is the net movement of electric charges through a material

-unit is Ampere (1 A = 1 C/s)

Current Formula

I= Q/t

RESISTANCE

-ability of a material to oppose electric charge -unit is ohm (Ω); 1 ohm is 1 volt per ampere (1 Ω = 1 volt/ampere)

Ampere

unit of current

Ohms

unit of resistance

Resistance Formula

R= V/I

ELECTRIC POWER

-rate at which electrical energy is converted to other forms of energy like heat, light, or mechanical -unit is watt (w) ( 1 watt = 1 j/s)

Watt

unit of electric power

Electric Power Formula

P=IV

ELECTROMOTIVE FORCES

-energy provided by a power source (battery or generator) per unit charge to move electric charge through a circuit.
-the push that makes electrons movement

CAPACITOR

-a passive two terminal electrical component that stores electrical energy in an electric field.

-has 2 conducting plate and an insulator called dielectric between the plates

-plates carry equal but opposite charges

- stores electric potential energy in the form of electric field

CAPACITANCE

-a measure of the ability of a material to store electric charge

Capacitance Formula

C= Q/V

DIELECTRIC

-the insulating material between the plates

DIELECTRIC CONSTANT

- measures a material’s ability to story electrical energy in an electric field. -how much a material can reduce electric field strength compared to a vacuum

Dielectric Constant Formula

Permittivity of the substance/permittivity of free space

k= €/€0

Parallel Plate

Capacitor na plates na magkatapat

Spherical Capacitor

Capacitor na Concentric spherical conductors

Cylindrical Capacitor

Capacitor na dalawang cylinder na nasa loob yung isa ng isa

Parallel Capacitor Circuit

-capacitors are parallel to each other

-voltages of each capacitor is equal

-charges are different

Capacitance of Parallel Capacitor Circuit

CEQ= C1 + C2 + C3

Voltage of Parallel Capacitor Circuit

VT = V1 = V2 = V3

Series Capacitor Circuit

-arranged in a chain

- charge is equal for all capacitors

-different voltages

Charge of Series Capacitor Circuit

QT=Q1=Q2=Q3

Voltage of Series Capacitor Circuit

VT= V1 + V2 + V3

Capacitance of Series Capacitor Circuit

1/CEQ= 1/C1 + 1/C2 + 1/C3

3 Properties of a conductor in electrostatic equilibrium

-zero charges inside

- excess charge are on the outside surface

- Equipotential Surface