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DHS PS Ch. 6/7
DHS PS Ch. 6/7 - Electricity (2015)
Question | Answer |
---|---|
What type of electric charge do protons have? | positive |
What type of electric charge do electrons have? | negative |
In most atoms, the charges of the protons and electrons do what to each other? | cancel each other out leaving the atom with no net charge |
Atoms become charged by gaining or losing? | electrons |
The accumulation of excess electric charges on an object is called? | static electricity |
The _____ ___ ______________ ___ _________ states that a charge may be transferred from object to object, but cannot be created or destroyed. | Law of Conservation of Charge |
Opposite charges do what when brought near each other? | attract |
Like charges do what when brought near each other? | repel |
Charges can act on each other even at a distance because ____. | any charge that is placed in an electric field will be pushed or pulled by the field |
Electrons move more easily through? | conductors |
An example of static electricity would be: | when you rub your feet on the carpet |
The rearrangement of electrons on a neutral object caused by a nearby object that is? | charging by induction |
A negatively charged balloon near your sleeve causes an area of your sleeve to become _______ charged. | positively |
A transfer of charge through the air between two objects because of a buildup of static electricity is called? | static discharge |
Using a conductor to direct an electric charge into the gound is called? | grounding |
The flow of charges through a wire or conductor is called? | electric current |
Current is usually the flow of? | electrons |
Electric current is measured in? | amperes (A) |
The push that causes charges to move is called? | voltage difference |
Voltage difference is measued in? | volts (V) |
For charges to flow, the wire must always be connected in a closed path or ______? | circuit |
What type of battery produces a voltage difference between its zinc container and its carbon suspension rod, causing current to flow between them? | dry cell |
What type of battery contains two connected plates made of different metals in a conducting solution? | wet cell |
What has a voltage difference across the two holes of an electrical outlet, and a generator at a power plant that provides this voltage difference? | wall sockets |
The tendency for a material to oppose the flow of electrons, changing electrical energy into thermal energy and light is called? | resistance |
All materials have some electrical _____. | resistance |
Resistance is measured in? | ohms |
Making wires _____ , ______ , or _______ increases the resistance of a wire. | longer, thinner, or hotter |
The current in a circuit equals the voltage difference divide by the resistance is called? | Ohms's law |
______ ________ produce a voltage difference across the outlets in homes. | Power Plants |
When the current has only one loop to flow through it is called a _____ _______? | series circuit |
Why are the parts of a series circuit wired one after another? | So the amount of current is the same through every part |
What is it called if any part of a series circuit is disconnected, no current flows through the circuit? | open circuit |
What is it called when a circuit contains two or more branches for current to move through? | parallel circuit |
In what type of circuit can individual parts be turned off without affecting the entire circuit? | parallel circuit |
Household circuits use what type of circuits that are connected in a logical network? | parallel circuits |
What contains a small piece of metal that melts if the current becomes too high, opening the circuit and stopping the flow of current? | electric fuse |
What contains a small piece of metal that bends when it gets hot, opening the circuit and stopping the flow of current? | circuit breaker |
Electrical energy is easily converted to? | mechanical, thermal, or light energy |
Electrical power is express in? | watts (W) |
What is static electricity? | a buildup of excess electric charge. |
What exerts the force that causes other electric charges to move? | the electric field |
Which has the weakest repulsion between charges? | like charges at a long distance |
Elements that are shiny and good conductors of electricity are | metals |
Why are metals good conductors of electricity? | Outer-level electrons are weakly held. |
The process of transferring charge by touching is called | charging by contact |
Because electric forces act at a _______, objects do not have to be touching to be affected. | distance |
According to Ohm's law, as resistance in a circuit __________, the current _________. | decreases, increases |
Electric charges always flow from | high-voltage areas to low-voltage areas |
Electric current in a circuit is measured in | amperes |
What is the push that causes charges to move? | Voltage difference |
What is the tendency for a material to oppose the flow of electrons called? | Resistance |
What is the standard voltage difference of electrical energy entering homes in the United States? | 120 V |
What is the standard voltage difference in circuits containing air conditioners and electrical dryers? | 240 V |
The purpose of fuses and cicuit breakers is to | prevent circuits from overheating |
The rate at which electical energy is converted to another form of energy is called | electrical power |
Electrical power is expressed in | watts |
Reistance is measured in a unit called | ohm |
The statement that current is equal to the voltage difference divided by the resistance is known as | Ohm's law |
Electric charge that has accumulated on an object is referred to as | static electricity |
A static discharge differs from an electric current in that a static discharge | lasts for only a fraction of a second |
A material through which electrons do NOT easily flow is a(n) | insulator |
If the leaves of an electroscope spread apart, it indicates that | the leaves of the electroscope have recieved a charge |
Lightning is _______ | a large discharge of static electricity between the sky and the ground. |
The carbon rod in a standard D-cell serves as | a conductor to transfer electrons |
Sources of constant electric current could be _____? | dry cell battery, wet cell battery, or outlet |
Which of the following is a device designed to open an overloaded circuit and prevent overheating by bending metal? | circuit breaker |
Electrical wires somethimes have a plastic coating wrapped around them. How does this make the wires safer to handle? | plastic is a good insulator |
Most of the electrical energy used by a toaster is converted to? | thermal energy |
After Tammy removes her sweater by pulling it over her head, she notices that her hair is standing straight up. What causes this to happen? | Her hairs now have similar charges causing them to repel each other. |
What exerts the force that cuases other electric charges to move? | the electric field |
The law of conservation of charge states that? | electric charge can not be created or destroyed |
The negatively charged particles in an atom are called? | electrons |
The rearrangement of electrons on a neutral object caused by a nearby charged object is called? | charging by induction |
According to Ohm's law, as the resistance in a circuit increases, the current _________? | decreases |
According to Ohm's law, as the resistance in a circuit _____, the current decreases. | increases |
In which type of circuit does current essentially have no resistance causing a circuit breaker to trip? | short circuit |
What contains a piece of metal that melts if the current becomes to high? | fuse |
What allows electrons to move through it easily? | conductor |
What contains a piece of metal that bends when it gets hot? | circuit breaker |
What detects the presence of electric charges? | electroscope |
V represents _______ ? | Voltage Difference |
Voltage Difference is measured in ______ ? | Volts |
P represents ______ ? | Power |
Power is measure in _____ ? | Watts |
I represents _____ ? | Current |
Current is measure in ______ ? | Amps |
E represents _____ ? | Electrical Energy |
Electrical Energy is measured in _____ ? | kWh |
t represents _____ ? | Time |
Time (when dealing with electricity) is measured in ____ ? | Hours |
R represents _____ ? | Resistance |
Resistance is measured in _____ ? | Ohms |
Vout represents ______ ? | Output Voltage |
Vin represents ______ ? | Input Voltage |
N1 represents ____ ? | Number of turns the primary coil |
N2 represents ____ ? | Number of turns in the secondary coil |
Name the two scientists that discovered electromagnetic induction. | Michael Faraday and Joseph Henry |
The generation of an electric current by a changing magnetic field | Electromagnetic induction |
Transforms ME to EE | Generator |
Transforms EE to ME | Electric motor |
In the U.S. |