Is it true that ohm's law states that current is directly proportional to the voltage and inversely proportional to the resistance?

Answer 1

No. Ohms Law states the relationship between voltage, current, and resistance, not between voltage, current, and charge. (Volts = Amps * Ohms)

Another Answer

Ohm's Law is not a universal law; in fact, it barely qualifies as a scientific law at all, because it only applies in a very limited number of controlled circumstances. Put simply, Ohm's Law states that 'the current in a conductor is directly proportional to the potential difference across that conductor, providing all physical conditions, such as temperature, remain constant'. So, as you can see, Ohm's Law only states the relationship between current and voltage.

Ohm's Law, then, ONLY applies when the ratio of voltage to current is constant for variations in voltage. Put another way, Ohm's Law only applies when the resulting graph of voltage to resistance is a straight line.

Unfortunately, this is rarely the case. For example, if you were to increase the voltage across a conductor, such as tungsten, the resulting increase in current would cause that conductor's temperature to rise, thus invalidating Ohm's Law, and producing a curved graph, rather than a straight-line graph.

So, Ohm's Law does NOT apply to most conductors, or to most electronic devices, such as diodes etc., other than for the straight-line parts of their characteristic curves.

Ohm's Law is frequently, but mistakenly, expressed by the equation, R = U/I (where R = resistance, U = voltage, and I = current). This equation, however, is derived from the definition of the ohm and NOT from Ohm's Law.

Answer 2

No. Ohm's Law relates voltage, current and resistance; it may be considered the definition of resistance. The law states:

V = IR (voltage = current times resistance).

Answer

Ohm's Law actually makes no mention of resistance; it merely states that 'current is directly proportional to voltage'(with certain provisos).

Resistance is only affected by the length, cross-sectional area, and resistivity of a conductor. As resistivity may change with temperature, temperature indirectly affects resistance.

Answer 3

Yes. All you need to do is understand the formula;

I = E / R Where I = Current

E = Voltage

& R = Resistance

If you substitute some simple values that can be computed in your mind, the relationship becomes clear. For example, if I give "R" a value of 4 and "E" a value of 12, the value of "I" can only be 3. However, if R remains constant at 4, and "E" is risen to 24 volts, by the formula given above, "I" increases by the same value. {the voltage doubled from 12 to 24, therefore, the current also doubled from 3 to 6}. This proves the mathematical direct proportionality of current to voltage. Inverse proof can be given if either voltage or current remains constant and resistance is varied.

Answer 4

No. Current flow through a constant resistance varies proportionately to the voltage applied.

Answer 5

No, the more voltage, the more the electrical current.