1 / 22

# electrical force - PowerPoint PPT Presentation

Electrical Force. Unit 1.3. Objectives. Explain the similarities and differences between Newton’s law of universal gravitation and Coulomb’s law. Explain how the force between two like charges and the force between two unlike charges are different. Describe how to create an electric field.

Related searches for electrical force

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

## PowerPoint Slideshow about 'electrical force' - paul2

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

### Electrical Force

Unit 1.3

• Explain the similarities and differences between Newton’s law of universal gravitation and Coulomb’s law.

• Explain how the force between two like charges and the force between two unlike charges are different.

• Describe how to create an electric field.

• Define electric potential difference or voltage.

• Differentiate between AC and DC .

• Identify the most common sources of DC voltage.

• Describe how to connect DC voltage sources so that voltages will add.

• Newton’s universal law of gravitation Every object in the universe attracts every other object with a force that is directly proportional to the mass of each body and that is inversely proportional to the square of the distance between them.

m1m2

N m2

Fg= G

Where G = 6.67 x 10-11

d2

kg2

• Charge – the property of an object that causes electrical force.

• Positive and Negative charges exist.

• Like charges repel

• Unlike charges attract (opposites attract)

+

-

• Both are inverse square laws

• Both give magnitude of the force one object exerts on another

• Gravitational force is always attractive, but electrical force can be attractive or repulsive.

• Gravitational forces govern large bodies

• Electrical forces govern smaller bodies

• Anatomy of an atom?

• Protons – Positive charge

• Neutrons – Neutral charge

• Electrons – Negative charge

• Normal atom has no net charge

• Electrons can move in some substances

• Principle of conservation of charge

• The net electrical charge in an isolated system never changes. (hair and comb)

• Charles Coulomb and his law

• The electrical force between two charged bodies is directly proportional to the charge on each body and inversely proportional to the square of the distance between them.

charges

q1q2

N m2

FE= K

Where K = 9.0 x 109

d2

C2

Distance

SI unit = Coulomb (C)

Elementary Charge - Charge on one electron or proton = 1.6 x 10-19 C

• The fields are the space between two masses or charges and the effects within them.

Opposite charges

Positive charge

Negative charge

Opposite plates

Like charges

• When charges are within an electric field an electrical potential difference is created.

• Volt – unit of measurement for potential difference. (electrical potential, voltage)

• Voltage is the prime mover in electrical systems (like pressure in fluid system).

Flow caused by “potential” difference

Fluid system

Electrical system

Current – Flow

A pump is a source of fluid pressure difference

A battery is a source of electrical potential difference

• Voltage source (battery or generator)

• Conductors (wires or circuit board)

• Control element (switch)

Electrical circuit

Control

Voltage source

conductors

• Direct Current (DC) – charge flows in one direction.

• Batteries

• Solar Panels

• Alternating Current (AC) – charge flows back and forth.

• Alternators

• Generators

• Cell – a single unit housing one or more chemical.

• Battery – consist of several cells

• How does it work?

• Chemicals react and electrons are removed creating a potential difference (voltage)

• Primary Cells – one time use batteries (cannot be recharged)

• Secondary Cells – Can be recharged

• Electrodes – the positive and negative terminals on a battery (cell).

• Positive electrode (red) called anode.

• Negative electrode (black) called cathode.

• Voltages add when cells are connected in series.

-

+

-

+

Battery

Battery

1.5 v

1.5 v

-

+

3.0 v

• An AC voltage source reverses the positive and negative terminals many times per second.

• The current flows one direction and then the other then the other…..

• This changing of polarity or cycling is called frequency, measured in cycles per second (hertz).

• The main source of 60hz current comes from electrical power plants, through power lines and into your homes.

• Generally 110 – 120 volts

• Some larger electrical devices need 220 – 240 volts.

• Newton’s law of universal gravitation and Coulomb’s law are both inverse squares laws. The magnitudes of both forces decrease with the square of the distance between the masses and the charges.

• Atoms are composed of proton, neutrons and electrons. Protons are positively charged, electrons are negatively charged, and neutrons have no charge.

• The flow of electrons in an electrical system is a current.

• Unlike charges attract, like charges repel.

• An electric field is a model of the alteration of space around one or more charges. You can use the field to predict the force exerted on a charge placed in a the field.

• The potential difference, or voltage, between two points in a uniform electric field is the product of the field strength and the distance between the points.

• Voltage is the prime mover in electrical systems.

• A battery is a source of DC voltage. It can maintain a current in an electrical circuit.

• Batteries or cells can be connected in series to increase voltage.