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Electricity and Magnetism. Test Review. Static Electricity. Def: Electricity created by a group of electrons staying together in one place. Electrons. Electric Charge. How can an object collect electrons to get an electric charge?. Electric Charge.
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Electricity and Magnetism Test Review
Static Electricity • Def: Electricity created by a group of electrons staying together in one place. Electrons
Electric Charge • How can an object collect electrons to get an electric charge?
Electric Charge • How can an object collect electrons to get an electric charge? • FRICTION!! - - - - - - - -
Types of Electron Buckets • What are buckets called where electrons stay put when they are placed inside?
Types of Electron Buckets • What are buckets called where electrons stay put when they are placed inside? INSULATORS: Rubber Plastic
Types of Electron Buckets • What are buckets where electrons are free to move around in?
Types of Electron Buckets • What are buckets where electrons are free to move around in? CONDUCTORS: Metal Water
Types of Electron Buckets • What is it called when a conductor is connected to the GROUND?
Types of Electron Buckets • What is it called when a conductor is connected to the GROUND? GROUNDING!
Multiple Charged Objects • Imagine two objects, one with +10C of charge and the other one neutral. No Charge +10C
Multiple Charged Objects • They are brought together and touch. Then are separated… +10C No Charge
Multiple Charged Objects • What charge does each object have now? ??? ???
Multiple Charged Objects • The total initial charge was split between the two objects. +5C +5C
Multiple Charged Objects • Complete the practice problem on you review sheet. ??? ???
Total Charge • Imagine two neutral objects. Then several electrons are sent form one to the other. What is the TOTAL charge of the WHOLE system? 1) 2) Electrons - + Neutral Neutral
Total Charge • TOTAL # of electrons and protons between both objects stays the same, so the TOTAL CHARGE on the SYSTEM stays the same. (Even though balloon is – and face is +) 1) 2) Electrons - + Neutral Neutral
Charge Interaction • Imagine a charged balloon and a pith ball…
Charge Interaction • What happens to the pith ball if the balloon is NEGATIVELY charged? -q
Charge Interaction • The ball is attracted to the balloon -q
Charge Interaction • What happens to the pith ball if the balloon is POSITIVELY charged? +q
Charge Interaction • The ball is STILL attracted to the balloon +q
Charge Interaction • What happens if the pith ball AND the balloon are both NEGATIVELY charged? -q -q
Charge Interaction • The pith ball moves AWAY from the balloon. -q -q
Electric Fields • Consider the electric field map below. • Recall: WWPD A B
Electric Fields • What is the charge on A and the charge on B? A B
Electric Fields • What is the charge on A and the charge on B? A + B -
Coulomb’s Law • Coulomb’s Law gives the force between two charged objects. • Be careful of units and scientific notation when working problems.
Coulomb’s Law • Coulomb’s Constant: • q1 and q2: charge on two objects • d: distance between the two objects
Coulomb’s Law • One hot air balloon flies through a thundercloud and comes out with a charge of -1000C. Another balloon below has a positive charge of +900C of charge. If they are separated by a distance of 200m, what is the electrostatic force between the two balloons?
Coulomb’s Law • Inverse square Law: • What happens if you double, triple, etc the distance??
Coulomb’s Law • Inverse square Law: • If distance is___________, F is _________. doubled ¼ tripled 1/9 quadrupled 1/16
Current Electricity • Current electricity involves electrons moving through conductors.
Current • Def: How fast electrons flow past a fixed spot. • Formula: • Current is measured in Amps
Voltage • Def: The amount of Potential Energy in a circuit. • Voltage is measured in Volts.
Power • Def: The amount of electricity that is used by an object. • Power is measured in Watts
Resistance • Def: Measure of how much electrons are slowed down when they go through a resistor. • Resistance is measured in Ohms (Ω)
The Formulas Q I t P I V V I R (Ohm’s Law)
Power Bills • To calculate a Power Bill, Power must be in kilowatts and time in hours. • Bill= rate*kW*h • Kilo: 1000 (1000 Watts in 1 Kilowatt)
Practice • Complete the practice problems for a classwork grade.
Circuits • Two main types of circuits • Series Circuit- One lane road • Parallel Circuit- Interstate
Ohm’s Law- WHOLE Circuit • What is Rtotal for the circuit? What is the current? 3Ω 5Ω 5V
Ohm’s Law- EACH Resistor • What is the voltage in each resistor? 3Ω 5Ω 5V
PARALLEL Circuits • Which resistor has the greatest current flowing through it? 2Ω 4Ω 10V
Magnets and Magnetic Fields • Magnetic Fields are SIMILAR to electric fields. • Consider the following magnet. 1 2
Magnets and Magnetic Fields • Fact: Field Line ALWAYS leave the North Pole and enter the South Pole 1 2
Magnets and Magnetic Fields • Which end is North and which is South? 1 2
Magnets and Magnetic Fields • Which end is North and which is South? N S
Magnetic Fields- Right Hand Rules Use your right hand!!!!
Right Hand Rule #1 • What does a magnetic field, B, look like around a wire? • Grab some wire with your RIGHT hand I