Electricity Unit Test Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

What is an ammeter?

A

An ammeter measures amps or amperes which is a measure of current (I). An ammeter has to be connected in series to measure amps and current.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is an ampere?

A

an ampere is how current electricity is measured. ex. 12 amps Amperes are measured on an ammeter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is charging by contact?

A

Charging by contact is when you rub 2 objects together and allow the electrons to move from one object to the other. This leaves one object positive (because it has lost electrons and therefore has more protons than electrons) and one left negative (because it has gained electrons and therefore has more electrons then protons)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the difference between charging by contact and charging by induction?

A

Charging by contact occurs when you rub 2 objects together and the electrons are transferred from one object to the other. Charging by induction occurs when a charged object is held near a neutral object and either attracts or repels the electrons creating a charge that is “induced” or left behind. ex. if a negatively charged object is held near a neutral object, the negative object’s electrons repels the electrons in the neutral objects and leaves behind a positive charge in that end of the object.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a circuit breaker?

A

A circuit breaker is like a safety device that prevents the cables and wires in your home from overheating and catching fire.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How does a circuit breaker work?

A

It works by the thermal expansion of metal like Christmas lights. A spring is held closed by a metal pin and when the pin gets hot it changes shape and allows the spring to push open the circuit stopping the flow of electricity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is a circuit diagram?

A

A diagram of how a circuit flows. It uses symbols to represent each component and is always a complete or closed circuit. This is an easy way to tell if a circuit is in series or parallel.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is a coal powered generating station?

A

It is a form of generating energy by burning coal to create heat to cause steam to rise.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How does a coal powered generation station work?

A

Coal is burned underneath water. this causes the water to heat up enough so that it ca change state into steam. The steam is hot so it rises and causes a wheel to turn which contains the magnet in the coil of wire and allows it to turn creating electricity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is conductivity?

A

The ability of materials to move freely to, from and within an object. Objects that allow electrons to move easily are called conductors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are examples of a conductor?

A

Metals (copper, silver.gold)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are fair conductors? Examples?

A

Fair conductors allow electricity to pass through with difficulty ex. Human body, salty water (the more salt, the more conductive), moist air, soil.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is current electricity?

A

The motion of electrons through a circuit. The electrons can be made to move by either turning a magnet in a coil of wire (generator) or by chemical reactions (like a battery). A circuit has to be complete or closed for electrons to be able to move.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is an electric current or current?

A

The number of electrons that flow. It is measured in amps or amperes on an ammeter that has to be connected in series in a circuit. It is represented by the letter I.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is an electrical circuit?

A

It is the path that electrons can flow. It includes a power source, a load and conducting wires (electrical wires). A circuit has to be closed for electrons to flow. Each circuit has a measure of voltage (volts), current (amps) and power (watts).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is electrical discharge?

A

It is the way that an object can lose its electric charge. This can either occur by contact with another object or grounding which allows electrons to flow in or out of an object to balance protons and electrons or you can discharge an object by a spark which is where electrons “jump” from one object to another due to a build up of charge.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is an electrical load?

A

Converts electrical energy into any other form of energy. Ex. a light bulb converts electrical energy into light and heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is electron affinity?

A

An objects desire for electrons. The triboelectric series orders materials based on their tendency to gain or lose electrons. An object with high electron affinity tends to gain electrons where as an object with a low electron affinity tends to lose electrons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is an electroscope?

A

It is an instrument that can detect an electric charge by showing the leaves of the electroscope spreading apart.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How does an electroscope work?

A

A charge is induced in the head of the electroscope. Based on the charge of the object, the electrons will either be attracted to the objects leaving only protons in the leaves causing the leaves to spread apart (because 2 of the same charges repel) or the electrons will be repelled by the object causing both leaves to be negatively charged and spread apart.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is friction?

A

The force resisting the relative motion of 2 surfaces in contact. Ex. rubbing 2 things together.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How does friction create electric charges?

A

Friction can be used to transfer electrons from one object to another. The force of the friction can be strong enough to allow electrons to be removed from one object and transferred to another. Some objects lose electrons more easily than others.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is a fuse?

A

It is like a circuit breaker and acts like a safety device that prevents circuits from overheating and catching fire due to a circuit going over it’s maximum current.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How does a fuse work?

A

A fuse melts below the circuits maximum current. The issue is that if the wrong fuse is put in, too much current could go through the circuit and cause the wires to heat up and catch fire.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is a ground fault circuit interrupter or GFCI?

A

It is a safety device. It is a wall outlet/plug that has a built in circuit breaker that will open the circuit if water enters it. They are used in places where water is near.

26
Q

How does a GFCI work?

A

When water is detected in the outlet, a short circuit is created which breaks the circuit through the house which allows for the houses electrical wires to be saved.

27
Q

What is grounding?

A

Grounding is when you touch a charged object to the ground or another surface with a conductor to allow for electrons to flow in or out of an object. This allows for a charged object to lose its charge because the electrons can either flow into or out of the object to balance electrons.

28
Q

What is a hydro electric generating station?

A

It generates electricity by using the flow of water to turn a wheel which turns a magnet in a coil of wire to create electricity.

29
Q

How does hydro electricity work?

A

A dam holds back a large amount of water and creates pressure. A small tunnel in the dam allows some water to flow through which turns a wheel which contains the magnet in a coil of wire.

30
Q

What are some pros and cons of hydro electricity?

A

Pros:

  • renewable
  • constant supply and flexible output
  • no waste
  • cheap to operate

Cons:

  • Expensive to build
  • creates flooding initially and stops flow of organisms up and down the river
31
Q

What are some pros and cons of using coal to produce electricity?

A

Pros:

  • fuel is relatively cheap and available
  • power plant is simple and cheap
  • flexible output

Cons:

  • pollution is a green house gas (CO2) and sulfur compounds contribute to acid rain
  • nonrenewable
32
Q

What are some pros and cons of nuclear energy?

A

Pros:

  • massive amounts of energy produced
  • fuel is very cheap and abundant in Ontario
  • no air pollution

Cons:

  • major consequence of an accident due to radioactivity
  • small amounts of very hazardous waste
  • very expensive to build
  • not flexible
33
Q

What are some pros and cons of wind energy?

A

Pros:

  • simple to operate
  • no pollution
  • renewable
  • small eco footprint

Con:

  • ugly and loud
  • must be windy
  • disrupts flight paths for birds
  • expensive to build
  • limited capacity
  • no flexibility
34
Q

What is induction?

A

Induction is when electrons move based on a charge that is held near by. E.g. a negative charge is held near a neutral object which repels the electrons in the neutral object making one end of it positive and one end negative. after induction, the 2 objects attract.
**induction does not change the overall charge of an object

35
Q

What is an insulator?

A

Materials that do not allow electricity to pass through. Ex. Rubber plastic and dry air. If an insulator is charged the charge stays at one end instead of spreading through the object because the electrons cannot move.

36
Q

What is a kilowatt-hour?

A

The amounts of kilowatts used in one hour. The charge for electricity is calculated by the number of kilowatt hours times the price per kilowatt hour.

37
Q

What is the law of attraction?

A

2 objects of opposite charges attract each other

38
Q

What is the law of repulsion?

A

2 objects with the same charge will repel each other

39
Q

What is lightning?

A

Lightning is a giant spark that jumps towards protons due to a build up of static charge.

40
Q

How does lightning occur?

A

Friction between falling ice and rising water creates a positive charge in the top of the cloud and a negative charge in the bottom of the cloud. The strong negative charge at the bottom of the cloud induces a positive charge (pushes electrons away) in the ground below it. When the charge in the cloud builds up enough it jumps down to the ground creating a giant spark.

41
Q

What is a nuclear powered generating station?

A

A nuclear powered generation station creates electricity by burning uranium to heat up water to turn the magnet in a coil of wire.

42
Q

How does a nuclear powered generation station work?

A

Uranium goes through reactions and heats up the warmer above and turns it to steam. The steam rises and turns a wheel which has a magnet in a coil of wire that creates electricity

43
Q

What is an ohm?

A

An ohm is a unit of measure of resistance. To find an objects resistance you do resistance=volume / current and you will get the number of ohms an object offers

44
Q

What is ohms law?

A

Ohms law is the equation resistance=voltage/current or r=V/I ohms law will find the amount of ohms or resistance an object offers

45
Q

What is a parallel circuit?

A

A circuit where the electrons have more than one path so the components line up parallel.

46
Q

What is potential difference?

A

Potential difference is equal to voltage. It is the amount of energy each electron has.

47
Q

What is power?

A

Power is the electricity requirement of a device. Power is measured in watts. To find the power you do power=voltage X current remember that 1000 watts is equal to 1 kilowatt

48
Q

What is resistance?

A

A measure of how hard t is for electrons to pass through an object.
It is measured in ohms using ohms law. (V=IR) The higher the resistance the power the current because it is harder for electrons to pass through.

49
Q

What is a resistor?

A

A resistor is an electrical component that provides resistance so that one side of the resistor has a higher current than the other. A resistor can also be used to lower the current. Each resistor is different because some materials resist electricity more than others.

50
Q

When is the most expenssive time to use electricity?

A

In summer: On peak in summer is 11am-5pm because people are usually home and using various appliances like air conditioning. Costs aabout 12.4 cents per kwh

50
Q

What is a series circuit?

A

When there is only one path that the electrons can follow. All components of the circuit are attached to each other and every electron flows through every component.

50
Q

What is a short circuit?

A

A connection within a circuit that has very little resistance which allows more electrons to flow through. This causes the wire to get hot and possible cause problems such as fire.

50
Q

What is static electricity?

A

A build up of charge is called static electricity. The charge is held on the surface and will build up until it has the chance to discharge through either a spark or by contact/grounding.

50
Q

What is a turbine?**

A

has blades on one end and as it turns the magnet in a coil of wire creates electricity. **

50
Q

What is voltage?

A

The amount of energy each electron has. Voltage is measured in volts using a voltmeter connected in parallel.

50
Q

What is a voltmeter?

A

An instrument used to measure volts in a circuit. To collect the information the voltmeter needs to be connected in parallel

50
Q

When is the cheapest time to use electricity?

A

In summer: 7pm-7am because most people run their air conditioning during the day in the summer so at night it is cheaper. Costs about 6.7 cents per kwh

50
Q

When is mid peak time for electricity?

A

In summer: from 7am-11am and 5pm-7pm because people are usually turning on and starting the day using electricity. It costs about 10.4 cents per kwh

50
Q

How is voltage divided across a series circuit? How is current divided?

A

Voltage: the voltage before each load and component is equal to the voltage on either side of the power source.
Current: equal actions whole circuit

51
Q

How is voltage divided across a parallel circuit? Current?

A

Voltage: equal across entire circuit
Current: the current of each tier or parallel set adds up to the current near the power source and before the first component

52
Q

What are the 4 things that effect resistance?

A
  1. Temperature (colder=better flow)
  2. Diameter (wider the better)
  3. Length (shorter the better)
  4. Type of material (some conduct better than others.)