Terms in this set (73)
A property of electrons and protons
The interaction between electric charges
The attraction or repulsion between electric charges
The region around a charged object where the object's electric force interacts with other charged objects
What happens to a charged object when it is placed in a magnetic field?
It is either pushed or pulled
Electric Field Lines
Represent the electric field and are drawn with arrows to show the direction of the electric force
Which direction does electric force usually point?
Away from the positive charges, always points towards the negative charge
The greater the distance
The weaker the electric field, strength is represented how close together the lines are
How many protons and electrons are in an atom?
Each atom has an equal number of protons and electrons
Conservation of Charge
Charges are neither created nor destroyed
Charging by Friction
The transfer of electrons from one uncharged object to another by rubbing
Charging by Conduction
The transfer of electrons from a charged object to another by direct contact
Charging by Induction
The movement of electrons to one part of an object that is caused by the electric field of a second object, which attracts or repels the second object
A way static electricity can build up on an object
Used to detect the presence of a charge, but it does not tell you if the charge is positive or negative because the charge on both leaves is the same
The loss of static electricity as electric charges transfer from one object to another (electrons transfer until both objects have the same charge)
The continuous flow of electric charges through a material
Rate of Electric Current
The amount of charge that passes through a wire in a unit of time and is measured in the ampere (amp. or A)
Producing Electric Current
Charges must flow continuously from one place to another
A complete, unbroken path through which electric charges can flow
A material through which charge can easily flow because atoms contain electrons that are bound loosely, so they can easily detach to flow from one object to another
Examples of Conductors
Medals and watery substances, especially ones that contain salts and acids
When are conductors used?
Carry electric charge and form electric current
A material through which charges can not easily flow because electrons are bound tightly to their atoms, so the electrons can not easily be detached, which is used to stop the flow of charges
Examples of Inductors
Rubber, glass, sand, plastic, and wood
Rubber coating on an appliance is an insulator so you do not get a shock
Electric Potential Energy
The energy an object has in result of position and charges inside the battery
Why do charges flow?
A difference in electrical potential energy
What do batteries provide for the circuit?
Potential energy difference
Voltage (Potential Difference)
The difference in electrical potential energy between two places in a circuit, measured in Volt (V)
What causes a current in an electric current?
Voltage (amount of force pushing an electric current)
A device that creates a potential difference in an electric current (batteries and generators are examples)
What causes charges to move around in a circuit?
The voltage between terminals
The measure of how difficult it is for changes to flow through a material
The greater the resistance,
The less current there is for a given voltage
Unit of measurement for resistance
Four Factors that Determine the Resistance
1. Material from which wire is made (conductors have low resistance because charges can move easily and insulators have high resistance)
2. Length ( long wires have more resistance that short wires)
3. Diameter (thin wire has more resistance than thick wires)
4. Temperatures (the electrical resistance of most materials increases as temperature increases)
"Path of Least Resistance"
The person is doing something the easiest way
Which path will the charge mostly flow through?
More of the charge will flow through the path with lower resistance
Energy stored in chemical compounds
What was Volta's first battery composed of?
Silver, Zinc, and paper soaked in salt water
How does an electrochemical cell produce current in a circuit?
One end of the cell reacts to loose an electron, which goes through the circuit. The other end accepts the electrons and reacts as well through a chemical reaction, so one end looses electrons, while one end gains electrons
A process in which substances change into new substances with different properties
A device that converts chemical energy into electrical energy
A medal strip that conducts electricity; a medal part of an electrochemical cell, which gains or looses electrons
A substance that conducts electric current
When chemical reactions occur between the electrolyte and the electrodes in an electrochemical cell, what do these reactions cause?
One electrode to become negatively charged and the other electrode to become positively charged
A combination of two or more electrochemical cells in a series
The type of electrochemical cell used as an energy source in a flashlight
The type of electrochemical cell in which the electrolyte is a liquid and found in automobile batteries
Measures the rate of electron flow through a circuit
Unit: amperes, amps (A)
Measure the energy available to move ("push") electrons through a circuit
Unit: volts (V)
Measure of how easily electrons flow through a circuit
High resistance = difficult for electrons to flow
Less resistance = more current
Easier for electrons to flow so flow more quickly
More resistance = less current
Harder for electrons to flow so don't flow as quickly
More voltage = more current
Electrons a given a bigger "push" so flow more quickly
Less voltage = less current
Electrons not given as big of a "push" so don't flow as quickly
Current Equation (Ohm's Law)
Voltage / Resistance
Only one path for electrons to follow
If one combat goes out then all will go out
Current: is the same through all components
Voltage: changes from point to point in circuit
Total Resistance: increases as you add more components
More than one path for electrons to follow
If one combat goes out it doesn't affect the others
Current: varies among the branches depending on the resistance in the branch
Voltage: is the same through all branches
Total Resistance: decreases as the number of branches increases
Rate at which work is done or energy is used
Rate at which electricity does work or provides energy
Unit: Watts (W)
Voltage X Current (Watts = Volts X Amps)
Measures how much energy used
Unit: kilowatt - hours (kWh)
What does the total amount of energy used depend on?
Total power used by all appliances
The total time they are used for
Power X Time (kWh = kW X h)
The resistance is equal to the voltage divided by the current
A device used to measure current
A device used to measure voltage
A device that contains a thin strip of medal that will melt if there is too much current through it. When the strip of metal blows or melts, it breaks the circuit, which stops flow of electric current
A reusable safety switch that breaks the circuit when the current gets too high. In some circuits, a high current causes a small metal band to heat up, which stops the current
Why is it important for people to avoid electric shocks?
Electrical signals in the human body control breathing, heartbeat, and muscle movement. If you receive an electric current from an outside source, it can result in a shock that interferes with your body's electrical signals.
When is a circuit electrically grounded?
Charges are able to flow directly from the circuit into Earth
What does the third prong of an electrical plug connect to?
Any metal pieces of an appliance to the ground wire of a building
A connection that allows current to take the path of least resistance