Electricity Review Sheet (with Study Quiz)
back to Navigator Science Page

ONLY ELECTRONS flow as a result of a (potential) difference
in electric charge.  Protons and Neutrons DO NOT flow.

Electric Field - an area where a charge exerts a force; the closer to the source, the stronger the force
Conduction - Occurs as 2 objects of differing charge touch; negative charge flows either to the object with a lack of electrons or from the object with extra electrons.
Induction - occurs as an object is moved near an object with an electrically charged field; no electrons are exchanged.  Electrons do, however, toward or away from the field within the objects (depending on the charges)
Ex. Conduction & Induction - the electroscope, the plastic rod on the rabbit hair Understand the theory behind Lightening and  Lightening Rods.

Direct Current (DC) - the movement of charge in one direction
Alternating Current (AC) - a reversing (back and forth) movement of charge

Voltage - the POTENTIAL for electrons to flow.  Units: Volts, symbol=V.
Current - the movement or flow of electrons.  Units: Amps, symbol=A.
Resistance - slowing or reducing the flow of electrons/charge.  Units: Ohms, symbol=?

Ex. You are powering a 22? heater with a 110V power source.  What amount of current is moving through the circuit?
Ans. V = I x R   >   110V = I X 22?     >    I = 110V/22?   >    I = 5 Amps

Ex.  How will the amount of current change if the voltage remains the same and the resistance is increased?  Ans.  The current will decrease.

Understand how and why fuses and circuit breakers work.
Fuse - a piece of conductor that breaks/melts if too much current goes through it; it is not reusable.
Circuit breakers - a switch that flips if too much current goes through it; it is reusable.

Understand the difference between dry cell and wet cell batteries.
Dry cell - the electrolyte is a paste; Ex. Flashlight and clock battery
Wet cell - the electrolyte is a liquid; Ex. car battery
 

Identify:  fuse, circuit breaker, dry and wet cell, resister, closed circuits and open circuits.

Ex.  Draw a series circuit (include a battery and 3 resisters).
 
 

Ex.  Draw a parallel circuit (include a battery and 3 resisters).
Your house is wired like a parallel circuit.


Electricity Study Quiz

1.  Give 2 examples of conductors. ___________________________________

2.  Give 2 examples of insulators. ____________________________________

3.  When the electroscope's foil leaves are charged and there is no contact with the charged plastic rod, this is an example of charge by  _________.

4.  When the electroscope's foil leaves are charged and there is contact with the charged plastic rod, this is an example of charge by  _________.

5.  Charge that moves in one direction is called ___________ current.
6.  Charge that moves in a back and forth direction is called _________ current.

7.  Give an example of a dry cell battery. ____________________
8.  Give an example of a wet cell battery. ____________________

Ohm's Law:       V = I X R
V = Voltage  I = Current  R = Resistance

9.  You are powering a 22? heater with a 110V power source.  What amount of current is moving through the circuit?  ___________________
 

10.  How will the amount of current change if the voltage remains the same and the resistance is increased?  ____________________________

11.  What is the function of circuit breakers and fuses?   __________________ ___________________________________________________________

12.  What advantage do circuit breakers have over fuses?   ________________
___________________________________________________________

13.  Is your house wired in series or parallel? ______________

14.  Draw how a lightening rod works:
 
 
 

15. and 16.  Draw and label a series and parallel circuit.  Include 1 battery and 2 resisters/loads.