What decreases when current increases?

Answer 1

Power = Current * Voltage

P = I*V


therefore for the same power, when the current decreases, the voltage increases

this is the concept that is used in Transformers for power transmission (increasing the voltage and reducing current to reduce power loss in transmission lines).

Answer 2

actually according to ohm's law at a constant temperature I directly proportional to v. there by keeping a const. 1/R we get v=IR. RESISTANCE depends on the physical parameters. R=s L/A. when the voltage rises there exists a voltage difference which increases there by increases the temperature rise occures which agitates the molecules of the resistor . this excitation causes the free movement of molecules which in turn increases the conduction and a fall in resistance..........

Answer

The simple answer is that it is temperature change that affects resistance, not the increase in current itself.

The resistance of a conducting material (any material, come to that) is affected by its length, cross-sectional area, and resistivity. As resistivity is affected by temperature, then resistance is indirectly affected by temperature -how much depends upon the type of material from which the conductor is manufactured.

For pure metal conductors, resistivity tends to increasewith temperature. So, if an increasing current flowing through such a conductor causes its temperature to rise, then its resistivity increases, causing its resistance to rise. For example, the resistance of the tungsten filament of an incandescent lamp increases quite markedly between its 'cold' temperature and its 'hot' (operating) temperature.

Some alloys are manufactured so that their resistivity (and, therefore, their resistance) remains constant over a wide range of temperature variations. The resistivity of insulators, on the other hand, falls with an increase in temperature, causing their resistance to fall with an increase in temperature -in fact, a high temperature is the major cause of insulation failure.