Electricity Review Flashcards
Electricity
physical phenomenon that results in moveable charges
Charge
fundamental property of certain subatomic particles (protons: positive, electrons: neg)
What does Charge do?
electrostatic force between +/-
conventionally we consider negative charged electrons to be the ones that move
How do we get charges in biological systems
dissociation of electrolytes (ions are the carriers of charge in the body)
(solution of electrolytes can conduct electricity)
Electric Potential (V), how does it happen?
when charged particles repel or attract each other they gain kinetic energy
when restrained from moving they have: electrical potential energy—-do math—and you get electrical potential (or voltage) (V)
Voltage def
an “electromotive force” (E)—basically electrical pressure that causes electrons to flow
Electric Current (I) definition
when electrons have potential and we allow them to move… you get current (I)
the amount of charge flowing through a conductor per unit time (its measure of flow)–(amps)
Definition of Current in the Body
movements of many ions of the same type in the same direction at the same time through a solution of electrolytes (sodium current, potassium current, etc)—we usually talk about currents along a cell membrane
Resistance { () } def
opposition to the unit of resistance (ohm)
Conductor
low resistance because their atoms don’t hold electrons tightly (metals)
Insulators
high resistance because their atoms hold electrons tightly (rubber, plastic, wood)
(in body—fatty membranes)
Conductance (G or g)
ability of substance or object to conduct a current (G=1/R)
Waterworks Analogy
V=water pressure
I=water flow
R{ ()}=restriction in pipe
Ohms Law
I=E/R
