Electric Charge
These types of charges attract
Opposite (+/-)
Ampere/Amp (A)
The slope of a Voltage vs Current graph (include units)
Resistance Ω (ohms)
Units for Electrical Power
Watts (W)
Like poles __________ and opposite poles __________
1. Repel
2. Attract
Objects become charged by gaining or losing these
Electrons
Causes electric charges to flow
Voltage Difference
In a voltage vs current graph, voltage goes on this axis
Y-axis
Units for Electrical Energy
Kilowatt x Hr (kWH)
The north pole of a compass points here
The south pole
Static Electricity
Material that allows electrons to pass through more easily
Conductor
If voltage (V) in a circuit is doubled, what happens to current (I) in the circuit?
It doubles as well. Directly related.
I = V/R
1.) I = 1v/1Ω = 1A
2.) I = 2v(doubled)/1Ω = 2A(doubled)
Calculate the power (P) generated by a 120v (V) outlet powering an electric drill drawing a current (I) of 3.2A
384W
P = I x V
P = ?
I = 3.2A
V = 120v
P = 3.2A x 120v = 384W
Nikola Tesla invented this type of current that reverses direction
Alternating Current (AC)
An instant transfer of electric charge (aka shock)
Static discharge
It decreases/goes down
What is the current (I) of a circuit with a 250Ω resistor (R) and a voltage (V) of 200v?
0.8A
I = V/R
I = ?
V = 200v
R = 250Ω
I = 200v/250Ω = 0.8A
A 120 volt (V) circuit powers a fan whose resistance (R) is 140 ohms. What is the power (P) of the electric fan?
102.9W
P = I x V I = V/R
P = ? V = 120v
V = 120v R = 140Ω
I = ? = 0.86A I =120v/140Ω = 0.86A
P = I x V
P = 0.86A x 120v = 102.9W
Draw the magnetic domains in an unmagnetized iron nail vs a magnetized iron nail.
Unmagnetized: Random orientation
Magnetized: Aligned with magnetic field
Explain how you can shock someone using the socks you are wearing and a carpeted floor. Be as specific as you can.
1. Charge yourself through contact/friction by rubbing your socks on the carpet
2. The electrons from the carpet are transferred to your socks and you become negatively charged
3. When you get close enough to a neutrally charged person, the excess negative charge you have repels the negative charges in the other person, creating a positive charge in the other person
4. The excess negative charges in you are attracted to the positive charges in the other person and jump from you to the other person creating a shock (static discharge)
A 9 volt (V) battery produces a current (I) of 30mA, according to Ohm's Law what would the value of resistance (R) be with correct units?
300Ω
I = V/R
I = 30mA => 0.030A
V = 9v
R = ?
R = V/I
R = 9v/0.030A = 300Ω
Using the equation for a line of slope of a line, explain why the slope of a voltage vs current graph represents the resistance in a circuit
Ohm's Law! I = V/R
Slope = Rise/Run = V/I = Resistance! R = V/I
Equation for a Line Y = mX => V = R x I
m = R
A Playstation5 draws 3.1A of current (I) from a 120v (V) outlet. If you play PS5 for an average of 50 minutes per day, how much does it cost per year to play a PS5 if electrical energy (E) costs $0.16 per kWH?
$18.03
E = P x t
E = ?
P = ? P= I x V = 3.1A x 120v = 372W=> 0.372kW
t = 50 mins => 50min/60minutes per H = 0.83H x 365 = 302.95H
E = 0.372kW x 302.95 = 112.7kWH
Cost = $0.16 x 112.7 = $18.03
Explain how an electromagnet works
There is power source (battery, outlet) connected in circuit with a solenoid (wire coil) wrapped around an iron object. When the current flows through the circuit, it creates a magnetic field that aligns the randomly arranged magnetic domains in the iron object with the magnetic field in the coil - creating a temporary magnet powered by electric current.