Electric Potential Energy and Voltage

Key Terms and Concepts

Battery -combination of electrochemical cells connected together(a single electrochemical cell)                                                                                     

• provides steady, controlled flow of energy                                                                                                                                                                 
•  chemical energy separates the positive and negative charges in a battery                                                                                                              
• classified into two different groups: wet cell, dry cell

Dry cell -the cylinder shaped electrolyte taken in the form of a moist paste                    

• e.g. flashlights, toys, remotes

Wet cell-  electrolytes that take form in fluid       

• e.g. (typically large vehicles) cars, motorcycles, airplanes

Terminal -end points of a battery where connection is made

Electrochemical Cell - cell that converts chemical energy into electrical energy stored in charges (typically called cells or batteries)

Energy -ability to do work 

• work= force x distance                                                                                                                                                                                           
• neither created nor destroyed, can only be converted from one form to another (Law of Conservation of Energy)

Kinetic Energy -energy a moving object possesses due to its motion (measured in joules)        

• 1/2 mv^2 (mass and velocity)                                                                                                                                                                                        
•  converted from potential energy   

Potential Energy -energy stored within an object (measured in joules)       

• measured as mgh (mass x gravitational acceleration x height)

Acceleration -increased rate or speed of something      

• converted into kinetic energy

Electric Potential Energy -electrical energy stored within a battery

• due to electrons possessing stored energy and ability to do work after leaving the battery        
• in order for electrons to lose their potential energy, the battery must be connected to a device

Potential Difference -amount of electric potential energy per one coulomb of charge

• factor to flow of electricity
• difference of electric pressure between two points
• work done to move a unit charge from one point to another
• joules/ coulombs (work done/ charge)
• referred to as Voltage
• unit for measuring potential difference/ voltage is volt (V)
• named in honor of Italian physicist, Alessandro Volta
• 1 volt= 1 joule/ 1 coulomb (when one joule of work is done to move one coulomb) simplified into (energy per charge)
• potential energy in battery is due to both the potential energy (volt) and amount of charge that has been separated
• energy that charge possesses is dependent on amount of charge and  potential difference/ voltage

Voltmeter -device that measures the amount of potential difference between two locations of charge separation

Electrode -two terminals of a battery

• usually made of two different metals but can be a metal and another material
• are in an electrolyte, a substance that conducts electricity and can be

Electrical Energy Sources                                                                                                                                                                                                         There are multiple forms that can be used to separate charges and provide electric energy. Here are a few examples. 

Friction - rubbing two materials together, work done by rubbing is converted into electrical energy stored into the separate charge

Generators -as the water falls it lands on generator, water field (electro-magnetism)

Thermocouples - consists of a loop of two wires of different metals joined at both ends, if one end is heated or cooled, charge is separated, and  potential difference/ voltage is created

Photo-electrochemical cells- when light hits the cell, some of the light energy breaks electrons off the surface of cell

Piezoelectric crystals -when collided  against, positive and negative charges are separated on either side of  crystal