Electricity

How does an ordinary lightbulb give off light?

When an electric current passes through the filament, it quickly heats up and becomes hot, giving off white light.

Charges flow easily through a circuit made of ________ wires.

metal

The voltage between the terminals cause charges to do what?

move around the circuit

What gases are contained in most ordinary light bulbs?

nitrogen and argon

Define electric current

the continuous flow of electric charges through a material

What is the amount of charge that passes through a wire in a unit of time

the rate of electric current

Do tungsten-halogen bulbs or ordinary lightbulbs give off more heat?

tungsten-halogen bulbs

How many terminals does a voltage source have?

two

What kind of rays do fluorescent lights give off?

ultraviolet rays

How is the flow of electric charges like a roller coaster?

A roller coaster requires potential energy to get start. So does a circuit. A circuit gets this energy from an energy source, such as a battery. If there is potential energy, then charges can begin flowing, or the roller coaster can move.

What is current measured in?

Amperes, amps (A)

Who was the ampere named for?

André Marie Ampère

If an electric circuit is complete, what happens?

Charges can flow continuously

How do vapor lights work?

When an electric current passes through the gas, the gas heats up. The hot gas then heats the sodium or mercury. The heating causes the sodium or mercury to change from a solid into a gas

How does a neon light work?

When an electric current passes through the neon, particles of the gas absorb energy. However, the gas particles cannot hold the energy for very long. The energy is released in the form of light

You don't get a shock from touching an extension cord because the cord a) has a three-pronged plug b) has two wires so the charges cancel c) is an excellent conductor d) is insulated with a rubber coating

d) is insulated with a rubber coating

What are conductors used to carry?

electric charge

Electric devices need electric charges that flow continuously, or ________ _________

electric current

When electric charges are made to flow through a wire or similar material, they produce an _________ __________

electric current

What process does a neon light use to produce light?

electric discharge through gases

True or False: Fluorescent lights get much hotter than incandescent lights.

false

True or False: Ordinary light bulbs are very efficient

false

True or False: The electrons in an insulator are bound loosely to their atoms and move inside the material

false; they are bound tightly to their atoms and do not move easily

How many factors determine resistance?

four

What color light do argon and mercury produce?

greenish-blue

Tungsten-halogen bulbs contain a small amount of what kind of gas?

halogens such as iodine or bromine

Resistance is the measure of what?

how difficult it is for charges to flow through a material

What is the lease efficient type of lightbulb

incandescent light bulbs

What are the four main types of bulbs?

incandescent, fluorescent, neon, vapor, CFL, and tungsten-halogen

The rubber coating on an appliance cord is an example of a/an _______________ (insulator/conductor)

insulator

The greater the resistance, the ________(more/less) current there is for a given voltage.

less

In a conductor, are atoms bound tightly or loosely?

loosely

What are insulators?

materials through which charges cannot flow easily

Would charges flow in wires made of plastic?

no

What is the unit of measure for resistance?

ohm (Ω)

What color light is produced my Krypton?

pale violet

What color light is produced my helium?

pink

What color does a true neon light light give off?

red

Rusty wheels on a roller coaster can be compared to _____________ in a circuit.

resistance

Current depends on what too things?

resistance and voltage

What are examples of insulators?

rubber, glass, sand, plastic, and wood

Which type of light bulb gives off a definite yellow color? a) fluorescent b) incandescent c) sodium vapor d) mercury vapor

sodium vapor

What are insulators used to do?

stop the flow of charges

What does the number of amps describe?

the amount of charge flowing past a given point each second

What can voltage be thought of as?

the amount of force pushing an electric current

As soon as a circuit is completed, what happens?

there is a continuous flow of electrons through all parts of the circuit

What is a spectroscope used for?

to view the different colors of light produced by a light bulb

True or False: The filament of a tungsten-halogen bulb gets much hotter than in an ordinary lightbulb

true

Do fluorescent lights give off most of their energy as visible light or heat?

visible light

The difference in electrical potential energy between two places in a circuit is what?

voltage

What is voltage measured in?

volts (V)

An object is luminous if...

it gives off its own light

How are ordinary lightbulbs like tungsten-halogen bulbs?

-Both contain tungsten filaments -Both give off a lot of heat -Both give off white light

What are the cons of CFL bulbs

-Contain mercury -Sometimes, they are not dimmable -They are not recyclable

How are ordinary lightbulbs different than tungsten-halogen bulbs?

-Tungsten-halogen bulbs give off more heat and light -Tungsten-halogen bulbs use less energy

What are the pros of CFL bulbs

-Very efficient -Come in multiple colors -Cost less over time

What are the factors that determine the resistance of an object (ex: wire)?

1) The material that the wire is made of 2) Length of the wire 3) Diameter of the wire 4) Temperature of the wire

Who was Georg Ohm, and what was named after him?

A German physicist who investigated resistance; the ohm, the unit of measure for resistance

Define vapor light

A bulb that contains neon or argon gas and a small amount of solid sodium or mercury

Define tungsten-halogen bulb

A bulb that has a tungsten filament and contains a halogen gas such as iodine or bromine

What does voltage cause?

a current in an electric circuit

True or False: Only some electrical devices contain electric currents.

False

What percent of an ordinary light bulb's energy is given off as light? What is the rest given off as?

Less than 10%; infrared rays (which is felt as heat)

What are some examples of good conductors?

Metals, such as silver, copper, aluminum, and iron

What is voltage?

The difference in electrical potential energy between two places in a circuit

Why are fluorescent lights so efficient?

They last longer than incandescent lights and use less electrical energy for the same brightness

What happens to neon gas particles after they absorb energy from an electric current? a) They hold the extra energy indefinitely b) They quickly discharge the energy in the form of light c) They convert most of the energy to heat d) The discharge the energy as electrical sparks

They quickly discharge the energy in the form of light

Why are most object you see visible?

They reflect light from some kind of light source

Why are vapor lights very efficient?

They require very little electrical energy to give off a great deal of light

Why are all neon lights not the color of neon?

They use different gases

Who patented the first practical incandescent light bulb and in what year did they do this?

Thomas Edison; 1879

What is the filament in an ordinary lightbulb made out of?

Tungsten

Are tungsten-halogen or ordinary lightbulbs more efficient? Why?

Tungsten-halogen bulbs are more efficient than ordinary bulbs because they give off more light and use less electrical energy

Lamps that use ordinary light bulbs often have cloth or paper shades. But tungsten-halogen lamps usually have metal shades. Explain.

Tungsten-halogen bulbs get much hotter than ordinary light bulbs

How does a fluorescent light work?

When an electric current passes through the bulb, it causes the gas inside to give off ultraviolet rays. When the ultraviolet rays hit the powder in the tube, the powder gives off visible light.

Define fluorescent light

a bulb that contains a gas and is coated on the inside with a powder

What is an electric circuit?

a complete, unbroken path through which electric charges can flow

What is a voltage source?

a device that creates a potential difference in an electric circuit

Charges in an electric circuit flow because of what?

a difference in electrical potential energy

Define incandescent light

a light bulb that glows when a filament inside it gets white hot.

What is a conductor?

a material through which charge can flow easily

What does current require to exist?

a path to follow

What is a neon light?

a sealed glass tube that contains neon gas

Which looks whiter: an ordinary lightbulb or a tungsten-halogen bulb?

a tungsten-halogen bulb

Fluorescent bulbs are more economical than incandescent bulbs because fluorescent bulbs give off more a) heat b) colors of visible light c) energy as visible light

a) energy as visible light

The filament is enclosed in an ________ glass bulb.

airtight

What is the abbreviation of an ampere?

amp or A

he unit for the rate of current is the ____________

ampere

Who was André Marie Ampère?

an early investigator of electricity

As electrons flow through a conductor, what do they form?

an electric current

What are examples of voltage sources?

batteries and generators

In a mercury vapor light, what color light is given off?

bluish

What kind of vapor lights are used for street lighting and parking lots? (sodium or mercury)

both

What are neon lights commonly used for?

bright, flashy signs

To produce electric current, what must happen?

charges must flow continuously from one place to another

If an electric circuit is broken, what happens?

charges will not flow

A voltage source is a device that can do what?

create a potential difference in an electric circuit

In a sodium vapor light, what color light is given off?

yellowish

Can electrons in conductors move throughout the conductor?

yes

An object is illuminated if...

you see it by reflected light