Grade 9 Science – Unit 4 – Electricity #2
Series and Parallel
Ohm’s Law Resistance, Current and
Voltage
More R, V and I plus Power and
Efficiency
Producing Electricity
1 1 1 1 1
2 2 2 2 2
3 3 3 3 3
4 4 4 4 4
5 5 5 5 5
A circuit with only one path
What is a Series Circuit?
It is the Voltage Load (Vload) across each load in a series
circuit when the energy source is 60V and three loads
occur on the circuit
It is the Voltage Load (Vload) across each load in a parallel
circuit when the energy source is 60V and three loads
occur on the circuit
What is 60V?
The voltage load is the same at each load as the energy source since each load in on its own
path and receives the full energy from the source
When the energy source is connected to this type of circuit, the electrons have different paths to follow
What is a Parallel Circuit?
It is the voltage drop across each load in a series circuit when there are two loads for
energy to cross
What is ½ the voltage drop
across the energy source?
In Ohm’s Law, the type of relationship between voltage, current and
resistance
What is Proportional Relationship?
The Ohm’s Law formula when solving for current
What is I = V / R?
If resistance is constant and voltage goes down, it
happens to current
What is Current decrease or goes down proportional to the
amount voltage decreased?
The voltage when a hair blower has a 24.0 Ω
resistance and 5.00 A of current running through it
when the blower is working
What is 120V?
V = I * RV = 24.0 * 5.00
=120.0
The straight line relationship between voltage and current
What is Ohm’s Law?
A measure of the RATE of electron flow past a given
point in a circuit
What is Electric Current?
What isthe amount of current needed to
stop the human heart from beating?
Note: A wall outlet delivers 15A of power
The difference in electric potential energy per unit of
charge measured at two different points in a circuit
What isVoltage
or Potential Difference?
The ability of a material to oppose
the flow of electric current
What is Resistance?
Length, Temperature, Type of Material
and Cross-Sectional Area
What arefactors that affect resistance?
The way a voltmeter is connected to a circuit to
measure the potential difference across a load
What is Parallel?
The device that measures resistance
What isan Ohmmeter?
The rate at which electrical power is produced or used
What is Electrical Power?
Comparison of the energy output of a device with the
energy supplied to the device
What is the efficiency of the device?
The percent efficiency of a light that uses 200 J of electrical energy and produces 50 J of light
energy
What is 25%?
% efficiency = Eout / Ein * 100= 50 / 200 * 100
= 25The light’s efficiency is 25%
Energy produced
when water
moves back and forth
What is Tidal Power?
Type of electrical energy produced when falling water turns a turbine
What isHydro-Electric?
It is how coal, oil and gas are used to turn
water into steam so the steam turns a turbine
Type of energy when thermal energy is moved from beneath the Earth’s surface and transferred
into a liquid
What is Geothermal Energy?
The type of energy that uses the movement of air
that is created by the natural processes of a convection current and the rotating of the Earth