Name:
Science 9
electric circuit
Date:
Unit 4 Review Key
GCCHS
This is the complete pathway that the electric current follows. It includes the
source, the load, the control and any meters present.
charged
This is a positive or negative electrostatic state that results from losing or
gaining electrons.
neutral
This is the state of being charged that exits on an object when the surface has
an equal number of protons and electrons.
electric current
This is the flow of electrons through a conductor.
static electricity
This term refers to stationary charges.
Laws of Charges
This is the law that states that, “like charges repel, unlike charges attract and
neutral objects will attract to any charge”.
insulators
These are materials that will not allow charges to flow through them easily.
Rubber, glass, ceramics and non-metals are good examples. They have a high
resistance.
conductors
These are materials that will allow charges to flow through them easily.
Metals are good examples. They will have a low resistance.
super conductors
These are materials with extremely low resistance. They occur at very low
(cold) temperatures.
grounding
This is the discharge of an object by connecting it to the ground. It is a
process that will send electrons into a positive object or remove electrons
from a negative one.
battery
This is a portable source of energy. It is a series of two or more cells. It
converts chemical potential energy to electric energy.
switch
This is a control in an electric circuit. It stops or starts the flow of electric
current.
resistor
load
amperes
This is a type of load in an electric circuit. It looks like this:
This is the part of an electric circuit that actually uses the electric energy to do
the work or produce heat and light. It may include a bulb, motor, resistor etc.
This is the SI unit of measure of current. It is symbolized by “A”.
galvanometer
This is a device to measure weak current in an electric circuit.
ammeter
This is a device to measure strong current in an electric circuit.
current
This is the measure how fast charges move through an electric circuit. It is
also known as voltage. It is symbolized by “I”.
potential difference
This is the measure in difference in energy per unit of charge between two
places in an electric circuit. It is also known as voltage. It is symbolized by
“V”.
resistance
This is the measure in difficulty that current has to flow through an electric
circuit. It is symbolized by “R”.
ohm
This is the SI unit of measure of resistance. It is symbolized by “Ω”.
Ohm’s Law
This is an empirical relationship between potential difference, current and
resistance in a circuit. Its formula is V = IR.
series circuit
This is an electric circuit that only has one possible path. This is an example:
parallel circuit
This is an electric circuit that has more than one possible path. This is an
example:
Power Grid
This term refers to the series of wires and cables that run throughout the
province that transports and stores electric energy.
Power
Step up Transformer
This is the measure of how fast energy is used or work is done. It is
symbolized by “P”. The SI unit for it is “Watts”.
This is a device that increases the potential difference and reduces the current
in order to transfer electricity through the power grid.
Step down
transformer
This is a device that decreases the potential difference and increases the
current in order to put energy in a form that is usable in the home.
Electric motor
This is a device that uses the interaction of electric and magnetic force to
convert electric energy to mechanical energy.
Electric generator
This is a device that uses the interaction of electric and magnetic force to
convert mechanical energy to electrical energy.
DC
Direct current. This is current that only flows in one direction in a circuit.
AC
Alternating current. This is current that changes direction in a circuit several
times each second.
P=IV
empirical
electric motor
This is the power formula.
This is the type of relationship that Ohm’s law is. It means that it is based on
experimental evidence, it is not theoretical.
This is a type of load in an electric circuit. It looks like this:
2) Calculate the resistance of a conductor if the voltage drop on it is 10.0 V and the current flowing
through it is 5.0 A.
𝑉
10.0 𝑉
𝑅= =
= 2.0 
𝐼
5.0 𝐴
3) What voltage is required across a conductor to produce a current of 4.0 A if the resistance in the
conductor is 10.0 ?
V = IR = 4.0 A x 10.0  = 40 V
4) An electric blender draws a current of 10.0 A and uses 120 V of potential difference. What is the
power used in this appliance?
P = IV = 10.0 A x 120 V = 1200 W
5) Draw a circuit with a 2 cell battery, 3 lamps in series, a voltmeter to measure the potential difference of
the source and an ammeter to measure the current.
6) Draw a circuit with a 4 cell battery, 2 lamps in parallel, a switch for each lamp, a voltmeter to measure
the potential difference of the source and an ammeter to measure the current passing through the 1st
lamp.