Introduction
In this unit we learned how to look at and analyze circuits as well as going into depth about what exactly is the electrical current that is flowing through the circuit.
Charge and Electrical Force (Coulomb's Law)
Electrical charge is when electrons move in an object either into or out of the object. This charge can be either positive or negative. If it has a negative charge then that means that there is a greater number of electrons than protons and if the object is positively charged then it has more protons than electrons. For a neutral charge, the number of protons and electrons are the same.
Elementary Charge- This is the smallest possible charge that can be isolated- 1.09x10^9 C. For this protons are positive and electrons are negative. The variable for charge is q and the unit for this is C which is a Coulomb.
Electrical force is the attraction or repulsion between two electrically charged objects. In this like charges will repel and opposite charges will attract. This is where the saying "Opposites Attract" comes from.
Coulomb's Law- The Electrical force increases as the charge increases but decreases as the distance between the two objects increases.
Elementary Charge- This is the smallest possible charge that can be isolated- 1.09x10^9 C. For this protons are positive and electrons are negative. The variable for charge is q and the unit for this is C which is a Coulomb.
Electrical force is the attraction or repulsion between two electrically charged objects. In this like charges will repel and opposite charges will attract. This is where the saying "Opposites Attract" comes from.
Coulomb's Law- The Electrical force increases as the charge increases but decreases as the distance between the two objects increases.
Electrostatic Induction- This is how one charge affects the charge in another object. There are conductors and insulators. In an insulator the electrons are fixed and cannot move so they do not transfer electricity well while conductors are the opposite. Their electrons are not fixed and therefore it is easier for them to move and effect electrical charges.
Electric Potential Energy and Electric Potential
Electric potential energy is similar to Coulomb's law. Since there is an electric attraction or repulsion between the two objects, it would take work to move them relative to each other. This equation for this work done is simply the electrical force multiplied by the distance travelled.
This image shows the relationship between Coulomb's Law and Electric Potential energy.
https://www.slideshare.net/cscottthomas/ch19-electric-potential-energy-and-electric-potential-online
https://www.slideshare.net/cscottthomas/ch19-electric-potential-energy-and-electric-potential-online
Now there is another aspect to Electric Potential Energy which is the difference of UE at different parts of the circuit which is the Voltage.
Circuits
Circuits are when there is an electrical current flowing in a loop and there has to be some electric potential difference which often comes from the power source. This is called the electromotive force that can do work on the system.
These are the parts of the circuit that are used to diagram them.
Note: For AP Physics 1 not all of these will need to be known.
http://www.jirvine.co.uk/Basic_Electricity/BE_tut_1/tutorial_1__what_is_electricity.htm
Note: For AP Physics 1 not all of these will need to be known.
http://www.jirvine.co.uk/Basic_Electricity/BE_tut_1/tutorial_1__what_is_electricity.htm
There are two types of Circuits
Parallel Circuits- There is more than one pathway for the voltage to go through. To find the resistance in a parallel circuit add up the reciprocals of the resistors and then take the reciprocal of that.
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Series Circuits- In a series circuit there is only on path for the voltage to go through. Therefore when finding the resistance of the resistors in the circuit all you have to do is add up each resistor value.
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Ohm's Law
Resistivity is the property of an object that opposes charge and it is determined by the structure of the material and the temperature.
Kirchoff's Law
Kirchoff's Loop Rule- The sum of all the voltages in the circuit is equal to 0.
Kirchoff's Junction Rule- The Current entering a Junction is equal to the current leaving the junction. Think of conservation of charge. There can be no new charge created or lost.
Kirchoff's Junction Rule- The Current entering a Junction is equal to the current leaving the junction. Think of conservation of charge. There can be no new charge created or lost.
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