What does Ohm's Law say?

Answer 1

The electric current flowing through a conducting material is directly proportional to the potential difference between its two ends,provided the temperature remains constant.

When temperature remains constant, the current flowing through an electric conductor is directly proportional to the potential difference across its ends.(V=IR)

Answer 2

Ohm's Law states that the current flowing in a conductor is directly proportional to the potential difference applied across that conductor, providing external conditions such as temperature remain constant.

Another way of expressing it is to say that Ohm's Law applies whenever the ratio of voltage to current remains constant for variations in voltage.

What Ohm's Law does NOT say is that 'current is voltage divided by resistance'! This is a misconception that many people, including many electricians, have about Ohm's Law.

Ohm's Law is by no means a universal law, and it onlyapplies to linear (or 'ohmic') conductors. So it does notapply, for example, to tungsten which is non-linear or non-ohmic, or to most electronic devices such as diodes.

Answer 3

Another Answer

Ohm's Law states that 'the current passing through a conductor is directly proportional to the potential difference across the ends of that conductor, providing various physical characteristics such as temperature, remain constant'.

In simple terms, for Ohm's Law to apply, the ratio of potential difference (voltage) to current must remain constant for variations in potential difference -in other words, if we plotted a graph of current against voltage, for variations in voltage, the result must be a straight line graph.

Unfortunately, this is very rarely the case. When this experiment is applied to most materials and devices the result is a curved line -which means that Ohm's Law doesn'tapply to those materials and devices! Devices that obey Ohm's Law are called 'ohmic' or 'linear'; those that do not obey Ohm's Law are called 'non-ohmic' or 'non-linear'. The overwhelming majority of conductors and electronic devices are non-ohmic!

From this, we can conclude that Ohm's Law is NOT a universal law, and doesn't apply to most conductors or devices, such as diodes, etc. In fact, there is a very good argument to say that Ohm's Law is NOT a 'law' at all! So one wonders why it is still being taught in schools and colleges as though it were a law! It's my opinion that Ohm's Law should NOT be taught at all!

The equation, generally taught as representing Ohm's Law (R = V/I) in fact doesn't derive from Ohm's Law at all, but from the definition of the ohm. This equation is true, whether Ohm's Law applies or not, and tells us what a circuit's resistance happens to be for any particular ratio of voltage to current.

Answer 4

ohms law states that, in an electrical circuit, the current passing through a conductor between two points is directly proportional to the potential difference(i.e. voltage drop or voltage)across two points,and inversely proportional to the resistance.

Answer 5

The statement I was taught in trade school fifty years ago was; "Current is directly proportional to the applied electromotive force and inversely proportional to the resistance of the circuit".The three equations of Ohms law are;

E = I x R, I = E/R and R = E/I.

I = Amps, E = Volts and R = Resistance.

Answer 6

Voltage = Current × Resistance
Ohms law states that the Voltage equals the Current times the resistance V =IR.

Answer 7

Current is directly proportional to the the applied EMF and inversely proportional to the resistance of the circuit.

Answer 8

V = I x R

Voltage = Current x Resistance