Notes: Name: __________________________

Stamps:

Directions: Fill in the blanks and boxes in the note panel. After notes are done, part of your homework is to fill in the sides with study questions and write a summary that demonstrates you understand what is important in the notes.

Simple CircuitsQuestions/Main Ideas Main Notes

• Whenever you separate + and – charges, you create a potential difference

• Potential difference is measured in _____ (V)• Voltage gives electrons an electric potential energy

o Ex:

• When separated, - charges will try to flow towards + charges

• This flow is called ________ (I)• In a battery, electrons will always flow from the – terminal

to the + terminal if they are given a path.

o Ex:

• You can put a device into this wire that changes the voltage to another form of energy. These devices are called resistors

• Resistors can covert ____________________ into:

• _________________ ex: light bulbs

• __________________ ex. toasters

• __________________ ex. Motion

• Most resistors convert electric potential energy into more than one type of energy.

o Ex:

• As long as the electrons can move from the negative to the positive, you have a ___________

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NOTES CIRCUITS - ELECTRICITY

Circuit diagrams

Draw 4 ways to light a bulb with one wire & battery

Inside a light bulb

• Each wire of the ________________

goes to a different ______________

of the battery

• This forces the current to flow through the

________________ in order to travel in a closed loop

Summary:

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ResistanceQuestions/Main Ideas Main Notes

•All materials give some _______________ to flow of charge•1 exception: superconductors

•___________ have a high resistance to electron flow

examples:

•___________ have a low resistance

examples

Amount of resistance depends on 3 things:

•______________

•______________ of wire

•______________of wire (_______________________)

Imagine a straw -- it’s easier to blow through when:

• ______________

• ______________

Resistance Formula:

• R ______________ (Ω = Ohm)

• L ______________ of wire (___)

• A cross sectional___________ of wire (___)

• ρ ______________ depends on material (___)

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Example:How much resistance is in the graphite of a 20.0 cm long pencil if the graphite has a diameter of 4.0 mm?

Summary:

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CurrentQuestions/Main Ideas Main Notes

Current = rate of __________________________

•q

•t

•I

1 Ampere =

Conventional current is the direction ______________ charges move

Actual ____________ flow is the ____________ way

•Current depends on two things:

1. Potential difference (_________)

2. ____________

Together, they make Ohm’s Law

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Water Circuit Analogy

Summary:

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Electric Shocks, Power and EnergyQuestions/Main Ideas Main Notes

1 mA =

10 mA = release current

100 mA = death

Power

Light bulb __________ depends on power

Power rate of energy usage

P =

New unit Watt

1 Watt (W) =

voltage = and current =

Unit Analysis: How could you calculate Power if given voltage and current?

Let’s combine ohm’s law (V=IR) with P=VI:

P =

P =

Twinkle, twinkle little star, power equals ________________

P = I2R

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Energy Equations

Plug in equations for Power and…

Important: know which units match your variables!

Name Variable UnitChargeTimeVoltageResistanceCurrentEnergyPower

Example 1:In 3.0 minutes an electric pot delivers 48,000 J of energy to the water inside it. The coffee pot is connected to a standard 120-volt source. What is the resistance of the coffee pot?

E=Pt

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Cost of ElectricityLet’s take a close look at the unit kilowatt-hour:

• kW =____• hr = ____ •Pt = _____

• kW-hr is a unit of __________

1 kW-hr

1 kW-hr =

Example 2:1 kW-hr costs $0.12:Find the cost of running a 60 W light bulb for 24 hours

Summary:

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Measuring ElectricityMeasuring Resistance: Ohmmeter

•Symbol:

• ________________ the resistor from circuit

•Place Ohmmeter leads on _______________________

Measuring Voltage: Voltmeter

•Symbol:

•Voltage source must be ________________ to circuit

•Place Voltmeter leads on _______________ of the source

Measuring Current: Ammeter

•Symbol:

•Need to ___________________ the circuit

•Force current __________________ by making the ammeter part of the circuit

Summary:

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Series and Parallel CircuitsQuestions/Main Ideas Main Notes

Series Circuit

IT = total current

RT = total resistance

VT = total voltage of battery

Current In order for the _________ to make it around the loop,

electrons have to flow at the same rate.

Resistance The current is _________ to pass through each resistor.

RT is also called the equivalent _____________

Voltage Each resistor lowers the _________ because resistors

convert electric potential into heat, light, or motion

This is called a voltage ______________

The voltage drops add up to the total battery voltage.

By the time the electrons reach the end of the circuit there will be no voltage left

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Example:

a. What is the total resistance inthe circuit?

b. What is the voltage of the battery the circuit?

c. What is the voltage drop at the 2nd resistor?

d. If the voltage drop at the 3rd resistor is 4V, What is the voltage drop at the 1st resistor?

R3 = 2Ω

R2 = 6Ω

R1 = 4Ω

IT = 2A

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Parallel Circuits

Voltage Imagine parallel as ____________________ connected.

Each uses the __________________________.

Current The total flow is _____________ into each branch-off

loop

Resistance

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Examplea. Find the total resistance if a 100 Ω, 200 Ω and a 300 Ω resistor are all in parallel to a 6.0 V battery.

b. Find the current through the 2nd resistor

c. What is the current through the ammeter?

Summary:

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Short circuits

• Electrons take the path of least _____________

Instructions:1. Highlight the path the current will take in circuits below.2. Circle the light bulb(s) that will light up.

Broken Circuit

Short Circuit

Summary:

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