: a very large amount or number: an amount that is much greater than what is necessary. A plethora of books have been written on the subject. a plethora of information. [+] more examples [-] hide examples [+] Example sentences [-] Hide examples. a very large amount or number: an amount that is much greater than what is necessary. A plethora of books have been written on the subject. a plethora of information. [+] more examples [-] hide examples [+] Example sentences [-] Hide examples.
Ohm's law defines the relationship between the voltage, current, and resistance in an electric circuit: I = V / R. The current is directly proportional to the voltage and inversely proportional to the resistance.
In electricity, if a pressure of one volt will drive a flow of one amp then the resistance is one Ohm. Two volts would drive 2 amps through 1 ohm: pressure divided by current equals resistance. In the water system resistance doesn't equate to anything useful as an aid to understanding. However 'resistance' is just that: the amount that the pipe 'resists' the flow of water. Double the water pressure and the flow will double. Double the length of the pipe and, if we didn't change the pressure, we would expect the flow to halve. This, in common sense terms, is exactly what Ohm's law says!