Static Electricity
a. Define conductor and insulator
b. Give an example of each
a. conductor- allows electrons to flow easily
insulator- does not allow the flow of electrons
b. conductors= metals
insulators= plastic, wood, rubber
a. This is the name of the chart used to predict the charge produced on a substance in charging by friction
b. Using this chart, determine the charge on cotton when rubbed with sulfur
a. The electrostatic series chart
b. cotton= +
a. Define AC current. What types of devices use this?
b. Define DC current. What types of devices use this?
a. alternating current- electrons move back and forth, alternating their directions. Anything using a wall outlet
b. direct current- electrons flow in one direction only. Anything that uses a battery to operate
a. Write the equation for calculating cost of electricity
b. Write the equation for determining the percent efficiency of something
cost= power x time x rate
%efficiency = Eout/Ein x 100
a. What are the 4 parts of a circuit? (NOT examples!)
b. What is the one part that you do not need in order for a circuit to still work?
c. Provide an example of each part of the circuit
a. Load, Energy Source, Connectors, Control device
b. control device
c. load= light
energy source= battery
connector= wire
control device= switch
a. Define semi-conductor/resistor.
b. Give an example.
a. allow the movement of electrons, but not as easily as conductors
b. graphite, silicon, a pencil
a. This is another term for charging by contact
b. Charging by contact end up with what type of charges? (opposite or the same?)
c. Draw a diagram of a negative rod coming in contact with a neutral sphere
a. conduction
b. same charges
c. teacher will confirm drawing is correct
a. Differentiate between renewable and non-renewable resource
b. Give an example of each.
a. renewable- can be replaced faster than it is consumed
non-renewable- is consumed faster than it can be replaced/a limited amount
b. R- falling water, wind
NR- oil, gas, fossil fuels
a. Define current and potential difference
b. What device is used to measure each?
a. current- the rate of electron flow past a specific point in a circuit
potential difference- also known as voltage, is the difference in electric potential energy per unit of charge at 2 points
a. current- ammeter
potential diff- voltmeter
b. Differentiate between an electric cell and a fuel cell
a. batteries and electric generating stations
b. electric cell= converts chemical energy into electrical energy, consists of 2 electrodes and electrolyte
fuel cell=a special kind of electric cell, a CONTINUOUS supply of chemicals is pumped as the cell operates, can operate for much longer
Distilled water is non-conductive, however water that comes out of a tap can conduct electricity. Explain how this is possible. What is it that allows the tap water to be able to conduct?
Tap water contains ions and minerals that can allow the movement of electrons (conductors)
b. Draw a diagram showing charging by induction, with a positive rod and neutral sphere
a. temporary- charge on neutral sphere remains neutral, however electrons move to one side of object. When charged object is moved away, the electrons return to their original position
b. Teacher will check if drawing is correct
a. Explain the benefit of EnerGuide and energy star labels.
b. What information do they each provide?
a. Provide consumers with average amounts of electrical energy a device will use in a year, allows consumers to make energy-wise choices when buying appliances
b. the energy star symbol identifies products that meet a minimum level of efficiency
the EnerGuide label identifies the amount of electrical energy used in a year
a. What are 4 factors that affect resistance?
b. Define ohmmeter and draw the symbol for it
a. type of material, cross-sectional area, length, temperature
b. ohmmeter- a device used to measure resistance
(teacher will confirm drawing of symbol)
Draw the correct symbols for a 3 cell battery, lamp, electric motor, open switch, voltmeter and ammeter
Teacher will confirm drawings
What are the 3 laws of electric charges?
a. opposite charges attract
b. similar charges repel
c. a neutral object can be attracted by a charged object
a. Define electric discharge
b. Electrons always move from the positive/negative object to the positive/negative object
c. Draw a diagram of lightning. Give a brief description of what is happening (be sure to include everything!)
a. the rapid transfer of electric charge from one object to another
b. Electrons always move from the negative object to the positive object
c. Water build up in the clouds causes the electrons to move to the bottom of the cloud. Electrons in the ground then repel away from the cloud, making the top surface of the ground essentially positive. Lightning is the rapid transfer of electrons from the cloud to the ground
a. How does the current compare/differ in a series vs a parallel circuit?
b. If more lights are added, what happens in a series circuit to the brightness? Parallel circuit?
a. Series- all lights have the same current
Parallel- all lights share the current
b. Series- they become dimmer as more are added
Parallel- they stay the same brightness
A load has 1.4 A of current flowing through it. The voltage across the load is 7.0 V. Calculate the resistance of the load. USE GRASS AND SHOW ALL STEPS!
Teacher will check answer
R= V/I
a. Draw a series circuit consisting of a 2 cell battery, a closed switch, 3 lamps and a fuse. Ensure they are in the correct order and you have all necessary parts of the circuit!
b. If the first light went out in the circuit what would happen to the rest of the light bulbs?
a. Teacher will confirm circuit drawing
b. they would all go out
Create a drawing showing charging by friction between two objects on the electrostatic series chart. Determine the charge each object starts with, AND ends up with!
Teacher will check and confirm answers
a. What is a lightning rod?
b. What is it made of?
c. Give an example of where you may find one in Ontario
a. Objects placed on top of tall buildings and structures to provide a safe pathway for lightning to follow to the ground
b. metal, such as copper or iron
c. CN Tower, etc.
Explain how a turbine/generator works. Use a diagram PLUS an explanation. (starting with a river flowing to getting electricity in your home)
water from river/dam flows and spins the blades of the turbine. The turbine is connected to the generator. the coild of wire is held between the magnet and as the turbine spins, this coil spins. This causes electrons to flow, through the wire, through the power lines to your home
A motor has a 23.0 ohm resistor that has 4 A of current going through it when the toaster is on. Calculate the potential difference across the resistor.
Teacher will check answer
V=IR
Draw the following circuit:
-3 cells in parallel
-2 lights in series
-a voltmeter measuring potential difference across one light
-a closed switch
-connecting wires
Teacher will confirm drawing