http://www.ck12.org Chapter 26. Glossary
26.5 E
efficiency
Measure of how well a machine reduces friction; calculated as the percent of input work that becomes output
work.
elastic force
Counter force exerted by an elastic material when it is stretched or compressed.
elasticity
Ability of a material to return to its original shape after being stretched or compressed.
electrical energy
Energy of moving electrons.
electric charge
Physical property of particles or objects that causes them to attract or repel each other without touching; may
be positive or negative.
electric circuit
Closed loop through which current can flow.
electric conductor
Material that has low resistance to the flow of electric current.
electric current
Continuous flow of electric charges due to a difference in electric potential energy, or voltage.
electric field
Space around a charged particle where the particle exerts electric force on other particles.
electric force
Force of attraction or repulsion between charged particles.
electric generator
Device that changes kinetic energy to electrical energy through electromagnetic induction.
electric insulator
Material that has high resistance to the flow of electric current.
electric motor
Device that uses an electromagnet to change electrical energy to kinetic energy.
electric transformer
Device that uses electromagnetic induction to change the voltage of electric current.
electromagnet
Magnet created by electric current flowing through a coil of wire that is wrapped around a bar of iron or other
ferromagnetic material.
electromagnetic energy
Energy, such as sunlight, that travels across space or through matter as electric and magnetic waves.
electromagnetic induction
Process of generating electric current with a changing magnetic field.
electromagnetic radiation
Transfer of energy by electromagnetic waves across space or through matter.
electromagnetic spectrum
Full range of wavelengths of electromagnetic waves, from radio waves to gamma rays.
electromagnetic wave
Transverse wave consisting of vibrating electric and magnetic fields that can travel across space.
electromagnetism
Magnetism produced by electric current.