Unit 5: Electricity Flashcards by Holly Hendry

Static Electricity

When you rub shoes on carpet charge is transferred. Shoes are now charged. STATIC

How well did you know this?

Not at all

Perfectly

How is the Law of Conservation in electricity?

The charges move. They are not created or destroyed.

How well did you know this?

Not at all

Perfectly

What does the type of charge depend on?

Whether there are more protons (+) or electrons (-)

How well did you know this?

Not at all

Perfectly

(++)
(–)
(+-)
(-+)

repel (like)
repel (like)
attract (opposites)
attract (opposites)

How well did you know this?

Not at all

Perfectly

What does the force of the electricity depend on?

Distance. Closer = more force. Farther = weaker force
Ex. Electrostatic machine –> When bars are close together they discharge. When bars are far apart nothing happens (no shock)

How well did you know this?

Not at all

Perfectly

What is lightning?

Collision of electrons with particles in the air. This creates light and heats the air up to 30,000C. The air expands and sound waves are created (thunder).

How well did you know this?

Not at all

Perfectly

What device detects a charge on an object?

An electroscope

How well did you know this?

Not at all

Perfectly

Lightning is the result of ________? Thunder is the result of _______?

Static electricity discharging

Heating the air molecules

How well did you know this?

Not at all

Perfectly

What is the equation for ohm’s law? What do each of the variables stand for?

V=IR
I=V/R
R=V/I
V: voltage (volts)
R: resistance (ohms)
I: current (amperes)

How well did you know this?

Not at all

Perfectly

What are the devices used to prevent circuits from overheating?
Explain how they work.

Fuses: the wire melts opening the circuit
Breakers: metal bends and the current is switched off

How well did you know this?

Not at all

Perfectly

When do the leaves of an electroscope separate?

When a charge is present the similar charge repels

How well did you know this?

Not at all

Perfectly

What is the equation for electrical power? What do the variables stand for?

P=IV
P: Power (watts)
I: Current (amperes)
V: Voltage (volts)

How well did you know this?

Not at all

Perfectly

What is the equation for electrical energy? What is the unit?

E=P(t)

kilowatt-hour

How well did you know this?

Not at all

Perfectly

How does lightning occur to the ground?

Changes separate on the cloud. Induces ground to be opposite. Discharge is the bolt.

How well did you know this?

Not at all

Perfectly

Why do we hear thunder?

Heating of the air to 30,000C causes the air to expand

How well did you know this?

Not at all

Perfectly

Why does a spark reach the doorknob when you walk across the carpet?

When dry, static electricity builds up –> discharges –> metal conducts

How well did you know this?

Not at all

Perfectly

Describe Atoms

Made up of protons and neutrons in the nucleus. Electrons on the outside. Protons are positive (+) and neutrons are neutral(0). Electrons are negative (-). Electrons can move. Atoms like to be neutral (same number of protons and neutrons).

How well did you know this?

Not at all

Perfectly

How can you tell if Christmas lights are in a series or parallel circuit?

When you unscrew one bulb if all the lights go out it is in a series if only one bulb goes out it is parallel

How well did you know this?

Not at all

Perfectly

Explain the electrostatic machine

Turn the wheel
Wheels spin in opposite directions
As the metal brushes rub together the charges separate
Static in the canisters
Discharge
Move the metal rods close together
- –>

How well did you know this?

Not at all

Perfectly

What’s the difference between static electricity and current?

Static: fraction of a second –> neutral
Current: flows due to voltage difference

How well did you know this?

Not at all

Perfectly

Why are electrons the particles that move, not protons? Draw an atom to explain.

Protons: in nucleus
Electrons: cloud or shell outside
Loose-conduct

How well did you know this?

Not at all

Perfectly

If more resistance, what happens to current? Explain?

Less current, more in the circuit, (people or bulbs)

How well did you know this?

Not at all

Perfectly

What happens to the current if more voltage? How do you get more voltage?

More current, more batteries (power source), higher volts

How well did you know this?

Not at all

Perfectly

Solve for OHMS law if I = 20 and R = 1.5

OHMS law: V = IR, I = V/R, R = V/I
V = 20(1.5)
V = 30.0
I = 20 amperes
R = 1.5 ohms
V = 30.0 Volts

How well did you know this?

Not at all

Perfectly

Electricity is __________ when electric ___________ accumulate on an object by gaining or losing __________ that move more easily in a(n) __________ than they do in a(n) _____________.

``` Static charges electrons conductor insulator ```

Electricity in the form of a ________ flows from object to object from _________ voltage to _______ voltage.

current high low

This voltage ___________ can be produced by a _______ or by a ___________ at a power plant.

difference battery generator

Electrical ___________ can be _________ with one _________ to flow through or they can be _________ with two or more ___________ for the electricity.

``` circuits series loop parallel branches ```

In what type of circuit will the brightness of the bulbs be diminished as more bulbs are added?

A series circuit

In what type of circuit will both lights go out if one light is turned off?

A series circuit

What type of circuit is used to provide electricity to houses?

A parallel circuit

A negatively charged object has ___________ electrons than an object that is neutral.

Electrons flow from areas of _______ voltage to areas of _________ voltage

higher | lower

Voltage difference is measured in _________.

volts

Electrons passing through a lamp ______ some voltage as they light the lamp

lose

Voltage _______________ in all parts of a series circuit

is the same

The current in a circuit is measured in ______________

amperes

Current is almost always the flow of ________

electrons

When a dry cell is connected in a series, the flow of electrons moves from the __________ terminal to the _________ terminal

positive | negatice

In a dry cell, the carbon rod releases electrons and becomes the ___________ terminal

positive

The voltage difference between the two holes in a wall socket is ___________

120 volts

A car battery is an example of a __________ cell

wet

Resistance is measured in _____

ohms

Copper has a __________ resistance to electron flow than tungsten

lower

According to Ohm's law, _______

I=V/R

The symbol for ohm is _______

omega (upside down horseshoe)

In the equation I=V/R, I is expressed in __________

amperes

In the equation I=V/R, V is expressed in ________

volts

THe _________ terminal of a dry cell identifies the location of the carbon rod

positive

A wire with a resistance of 3 Ohms has a _________ resistance to electron flow than a wire with a resistance of 5 ohms

lesser

If two copper wires are the same length, but different thicknesses, the _________ wire has greater resistance

thinner

What are the two types of circuits?

Parallel | Series

Definition of: series circuit parallel circuit

Series circuit: The current has only one loop to flow through. parallel circuit: The current has more than one branch.

Too many appliances in a circuit can cause a

fire | insulation to melt

For protection, household circuits contain

fuses that melt a wire and open the circuit | circuit breakers the switch flips and the circuit is open

Definition of electrical power

Rate at which electrical energy is converted to another form of energy

``` Unit of electrical power: Name- Abbreviation- Term for 1,000 units- Abbreviation for 1,000 units- ```

Watt W Kilowatt KW

Determining the electrical power of a circuit: Expression- Formula-

Power = current X voltage | P=IV

A power rating lists the ___________ required to operate an appliance.

watts

A closed path through which electrons can flow is _______

a circuit

A fuse will melt if the _________ in a circuit becomes too high

current

Current is almost always the flow of ________

electrons

A current has two or more branches in a ___________

parallel circuit

A car battery is an example of a ________

wet cell

The tendency for a material to oppose the flow of electrons is called _________

resistance

Current has only one loop to flow through in a ________

series circuit

Current is measured in _________

amperes

Electrical energy is equal to _________ X time

power

Electrical power is equal to __________ X voltage difference

current

Ohm's law states that the current equals _______ divided by the resistance

voltage difference

A dry cell is used in a flashlight to convert ________ to light

electrical energy

Thin wires have a ___________ resistance to electron flow than thicker wire do

greater

One thousand watts of power used in 60 minutes is _______

1 kilowatt-hour

What are the 4 necessities for a circuit?

1. Power Source (battery - pushes electrons) 2. wires "conductor" 3. device (like a light bulb) 4. switch (on and off)

Define insulator

Something that electricity does not move through easily

Define conductor

Something that electricity does move through easily

Define series

A circuit with only one path

What are some insulators?

Clothes | Shoe laces

What are some conductors?

Earring Ring Copper wire lead on a pencil

Define parallel

A circuit with two or more branches

A measure of the amount of energy used to move 1 coulomb of electrons

voltage

a complete path through which a current travels

electric circuit

a measure of how difficult it is for an electric current to flow through a material

electric resistance

The unit used to measure electric resistance is the

ohm

Describe the relationship between electric resistance and the flow of electric current in materials

Good conductors have low resistance

What type of copper wire has low resistance

short, thick wire

If the current and resistance in a circuit are known, the voltage can be determined by

multiplying the current and resistance

How to determine the amount of voltage each device is getting in a circuit

Divide the voltage by the number of devices

The current flowing through an electric lantern is 0.25 A, and the resistance is 48 ohms. What is the voltage of the lantern battery

V=IR V=0.25(28) V= 12 12 Volts

A small motor is labeled with a current rating of 3 A and a resistance of 40 ohms. What voltage does the motor run at?

V=IR V=3(40) V=120 120 Volts

A DVD player that has a resistance of 40 ohms has a current of 0.1 A flowing through it. How many volts supply the DVD player?

V=IR V=0.1(40) V=4 4 Volts

A neon sign that has a resistance of 50,000 ohms has a 0.06 A current passing through it. What is the voltage across the neon sign.

V=IR V= 0.06(50,000) V= 3,000 3,000 Volts

Unit 5: Electricity Flashcards

(92 cards)