Electricity Quiz #1 Flashcards
(34 cards)
1
Q
What is a static electric charge?
A
An imbalance between electrical charges on a material’s surface.
ex. positively charged body touches negatively charge door knob
2
Q
How is static charge produced?
A
- friction between 2 surfaces lead to a gain or loss of electrons
ex. feet on carpet
3
Q
What is an electroscope?
A
- A device that detects charged objects
- It will show an attracting or repulsing action if a charged object is brought near
ex. Pith ball on string moves closer or farther away from object depending on charge
4
Q
What has an electric charge?
A
- An atom that has lost (Positive) or gained (Negative) electrons
5
Q
How are charges on objects created?
A
-
6
Q
What is a conductor and insulator?
A
- a conductor (metal) is used to transfer charge between objects
ex. wires - an insulator stops the flow of electrons
ex. rubber, plastic covering wires
7
Q
What are the rules of static electricity?
A
- objects with like charges repel one another
- objects with opposite charges attract one another
- charged objects attract neutral objects
8
Q
What are some rules of generating electricity?
A
- energy is neither created nor destroyed
- it is transformed from one kind of energy into another
9
Q
What is kinetic and potential energy?
A
- k.e. is the energy of motion
- p.e is the energy stored in a system/object due to its position or condition
- together, these are mechanical energy
10
Q
What is chemical energy
A
- energy stored in bonds within molecules
- energy is released when a chemical reaction occurs
- mitochondria converts glucose molecules to energy useful for cell by getting energy from the bonds
- batteries use chemical energy by storing molecules and ions in their structures allowing electrons to transfer between them
- fossil fuels (coal, oil, and natural gas) store chemical energy
11
Q
Kinetic energy –> Electrical energy
A
- steam, water, or wind spins turbine and shaft
- the shaft connects the turbine to the generator
- the kinetic energy of the shaft is converted to electrical energy in the generator
- As the shaft turns the wire loop/coil in the generator, there is a magnet surrounding it and electrons flow in the wire (current)
12
Q
What is solar energy?
A
- energy carried by sun
- fossil fuels and biomass are result of plant capturing sun’s energy
13
Q
What is nuclear energy?
A
- nuclear fusion (smaller atoms collide to form new atoms) happens in stars to generate energy
- nuclear fission (larger, unstable atoms split) happens in reactors on earth to generate energy
14
Q
What is thermal energy?
A
- rapid motion of particles that make up an object (KMT, heat)
- It can come from nuclear reactions, earth’s interior…etc.
- volcanoes and hot springs form steam to move turbines
15
Q
How do solar panels work?
A
- panels are made of silicon sandwiched between different conductive layers and is connected to its neighbours by 4 chemical bonds
- The movement of electrons in solar cells make a positive and a negative side of the cell
- electrons naturally push to one side of the cell to be collected into thin wires.
- the most efficient solar cell right now is 46%
16
Q
How is it like in a nuclear power plant?
A
- Uranium atoms are split into smaller atoms by a neutron (this is called a fission)
- The unstable uranium separates to form 2 smaller atoms & 3 neutrons that continue the chain reaction of hitting other uranium atoms
- water is required to slow the neutrons and cool the reactor to prevent a nuclear explosion
17
Q
What is an electrochemical cell?
A
- devices that convert chemical energy into electrical energy
- when two or more cells are combined together, we call this a battery
18
Q
What is the structure of an electrochemical cell
A
- the chemical energy isolates the negative terminal and positive terminal of the cell
- when a battery is connected to a device using wires, the electrons travel from the negative terminal –> device –> positive terminal to complete the circuit
19
Q
What is a circuit?
A
- a path for the electrons to follow
20
Q
What are the 4 components necessary for an electrochemical cell to function?
A
- negative terminal that accepts electrons
- positive terminal that gives up electrons
- electrolyte that removes electrons from the positive terminal by chemical reaction
- separator that keeps electrons separate from the positive terminal
21
Q
What is work?
A
- moving something by applying a force (push, pull) over a distance
22
Q
What is energy?
A
- ability to move something by applying force
23
Q
What is electric potential energy?
A
- electrical energy stored in a battery
- electrons have Electrical potential energy
- it depends on charge amount and separation = volts
ex. chemical reaction in battery provides the electron with a push = charge separation which leads to chemical potential energy
-volts
24
Q
How is energy like a staircase?
A
- bottom of stairs no P.E.
- top of stairs lots of P.E.
- P.E. of person on stairs = height of stairs and mass of person
- going through the circuit, the e- will use the electrical P.E. that has been given to it in the battery
25
What is a coulomb?
- A unit of which charge is measured
- one coulomb = 6.24 x 10^18
26
How is current measured?
- Current = Amperes (Amps)
- Amps = 1 coulomb per second
27
What is a voltmeter?
- a device that measures the amount of electrical potential energy (Volts) between 2 locations of charge separation
28
What is electric current?
- the amount of charge (measured in coulombs) passing through one point in a conductor every second
- measured in units called amperes or amps (A)
- ammeter is a device used to measure current in a circuit
- often referred to as flow of electrons
ex. phone charger uses/draws 1.5 A of current
29
What is conventional current?
- original idea before discovery of electrons was that current flowed from positive to negative and the positive particle was moving
- we still use the term conventional current to describe flow from positive to negative because it is so entrenched in our past understanding
30
What is electrical resistance, and what is it measured with?
- slows the flow of electrons and converts electrical energy into other forms of energy (heat, light, sound, etc.).
- measured in units called ohms using an ohmmeter
- ohmmeter applies a voltage and measures the current in the circuit
31
What are the 4 basic components in a circuit?
- chemical cells as a source of electrical energy (batteries)
- conductor as a wire for electrons to flow through
- load as a device that transforms electrical energy into other forms of energy
ex. light bulb, buzzer, heater, motor
- switch to turn circuit on or off
32
What are the rules to follow when drawing circuits?
- draw with a ruler
- connect wires and leads should be straight with 90 degree corners
- finished drawings should be square or rectangle
- try not to overlay conductor lines
- use specific symbols to represent the components
33
What is the symbol for voltmeter, motor, light bulb, and ammeter?
- circles with v, m, filament, and a
34
What is the symbol for conducting wire, electrochemical cell, battery, resistor, open switch, and closed switch?
line, 1 cell line, 1+ cell line, squiggle line, open line, closed line
