Electricity

Electric current is the flow of _____, pressured (pushed or driven) into motion by _____, and hampered by _____.

Charge, voltage, resistance

Direct current (DC):

Charges only flow in 1 direction; negative charges move from a lower to higher electric potential

Positive & negative charges in motion are called _____.

Charge carriers

potential difference:

Charge flows (technically charged particles flow) from one end to the other

_____ can be charged by contact if you hold a metal with an insulated material and then rub it

Conductors

Charging by induction works on _____ & _____.

Conductors & insulators

There is a similar relationship between force, charge, and distance -

Coulomb's law

Charging by contact:

- materials become charged when rubbed together (friction) - charge can be transferred with contact

Why is the overall charge of the atom neutral?

- Equal number of protons & electrons. - The charge of an electron is equal in magnitude but opposite in sign to the charge of a proton.

Electrical power is the:

- Rate of conversion of electrical energy - rate of energy transfer

Batteries or electric generators:

- good pumps in electric currents - can maintain a steady flow of charges

Potentiometers:

- special type of resistor - contains an adjustable, sliding contact that allows the user to adjust resistance (ex.) dimmer switches, volume control, game controllers (1 for x direction, q for y)

Each _____ has a charge of -e equal to -1.6x10^-19 Coulomb (C)

Electron

Ohm's Law

The relationship of voltage, current, and resistance

Charge returns to the battery; potential energy is _____

0 - battery does work on the charge

Conservation of charge:

1. Charge is conserved 2. Electrons are simply transferred from 1 material to another

Moving charges that make up a current can be:

1. Negative (moving electrons in solid conductors) 2. Positive (protons are set in motion in particle accelerators) 3. Combination (in gases & dissolved salts, positive charges move in 1 direction, negative charges move in the opposite direction)

2 types of charges:

1. Positive 2. Negative

What does the nucleus of an atom contain?

1. Protons (positive charge) 2. Neutrons (neutral charge)

Factors that affect resistance:

1. length: longer has greater resistance 2. cross - sectional area: skinny has greater resistance 3. Temperature: higher temp = greater resistance 4. material *So, if you want the least amount of resistance, you would want short, fat, cold*

*know how the current levels effect the human body* 1. 1 mA 2. 5 mA 3. 6-30 mA 4. 50-150 mA 5. 1000-43000 mA 6. 10,000 mA

1. slight tingly sensation 2. slight shock - you can let go of the object 3. painful shock - muscular control is lost, freezing current or "let go" range 4. extreme pain, respiratory arrest, severe muscular contractions - cannot let go. possible death 5. heart stops (pumping action ceases), nerve damage, death 6. cardiac arrest, severe burns, DEATH

When wet (soaked in salt water) human skin has a resistance of _____

100 - Ions in salt water conduct electric charge

Energy delivered in 1 hour at the constant rate of _____.

1kW

When dry human skin has a resistance of _____

500,000

In the US, AC oscillates _____

60 times per second -> 60 Hz

When released, the particle _____ away from the charged body.

Accelerates - PE electric becomes KE

Current transferred to homes/businesses by power companies is _____.

Alternating current (AC)

The rate of electrical flow is measured in _____, which is the rate of flow of 1 Coulomb of charge per second (C/s)

Ampere (A)

_____ will continue as long as there is a potential difference

Current (the flow of charged particles)

The _____ is considered to be an infinite reservoir for electrons because it can accept an unlimited amount of electrons.

Earth

The _____ is the fundamental quantity that underlies all electrical phenomena

Electric charge

The motion of electric charges is known as _____

Electric current - In metal wires, electrons make up the flow of the charge

Semiconductors:

Electric properties are somewhere between conductors & insulators: - pure state - insulators - when specific materials are added as impurities they become conductors - metalloids (along the stair steps of the periodic table)

_____ Is the force that one charged particle exerts on another charged particle, causing acceleration either toward or away from each other.

Electrical Force

_____ is the name given to a wide range of electrical phenomena that underlie most things around us - from lightning to the spark when a match is struck to the bond holding atoms together.

Electricity

What surrounds the nucleus?

Electron cloud - electrons (negative charge)

Superconductors:

Have 0 electrical resistance when they're at or below a certain temperature: - can conduct electricity indefinitely without heating up

Polarization is a process similar to charging by induction & it works on _____.

Insulators

_____ can be charged by contact

Insulators

Energy from battery is converted to _____ due to collisions b/w charge carriers & other particles in conductor.

Internal energy

The _____ ranks with the laws of conservation of energy and momentum, as a significant fundamental principle in physics.

Law of conservation of charge

_____ charges repel

Like

An electric field has both _____ & _____.

Magnitude (strength) & direction

Electrical insulators:

Materials in which electric charges don't move freely. - glass - rubber - silk - plastic

Electrical conductors:

Materials in which electric charges move freely. - metals

Overall charge of the atom is _____.

Neutral

Insulator has _____ net charge, but it is still able to attract or repel objects due to _____.

No, realignment

_____ charges attract

Opposite

_____ will cause energy to flow from high to low energy.

Potential difference

Each _____ has a charge of +e equal to +1.6x10^-19 Coulomb (C)

Proton

Electrons _____ results in a negative ion (more electrons than protons)

Received - anion

_____ occurs because of the internal collisions between the charges as they're moved along by the potential difference

Resistance - internal friction

Induction:

The process of charging a conductor by bringing it near another charged object while the conductor's grounded

Alternative current (AC):

The terminals of the source of potential difference constantly change sign

Electrons _____ results in a positive ion (more protons than electrons)

Transferred - cation

Resistors:

Ways to adjust the current in a conductor

Charge is only transferred in _____ multiples of the charge of an electron, never in a fraction of the charge.

Whole-number

Charge moves _____ the terminals of the battery (D to A)

between

Electrical potential energy increases by qV (where V is the potential difference across the battery terminals) -Battery's chemical energy _____ by the same amount.

decreases

motion of electric charges =

electric current

Power companies charge for _____, not power

energy used

When some materials (like copper, aluminum, silver) become charged in one small area, the charge distributes itself over the _____ of the material.

entire surface

Electrical force acts from a distance and is known as a _____ force.

field

Work done _____ the electric potential energy of the particle.

increases

Without the _____, the charges that are produced by rubbing move through the metal, then through your body (also a conductor), and ends up in the Earth (going to ground or being grounded)

insulator

In the filament, electrical energy is converted to _____.

internal energy; the filament warms up & glows

The _____ charge the charged object has, the stronger the electric field that 3D surrounds it.

larger

From B to C, _____ of electrical energy due to the resistance in the bulb filament.

loss

Disregarding the resistance wire, _____ of energy occurs as the charge moves from A to B.

no loss

Electric current moves _____ the movement of the negative charges known as conventional current

opposite

A charged object has _____ energy due to its position in an electric field.

potential

Electric potential energy:

the energy the particle possesses because of its location

Objects are charged by _____ electrons from one place to another. This can occur by contact (rubbing or simply touching) or by bringing a charged object nearby, called _____.

transferring, induction

Potential difference =

voltage

_____ (electric potential) is analogous to pressure for fluids

voltage