Hi I am new to this forum According to Ohms law, at constant temperature voltage is directly proportonal to current.
But when we come to power formula p=vi which means that V is inversly proportional to I. How can we justify this?
Thanks to all in advance.
First of all,
Ohm's law is
not V=I*R, and all its variations. Regardless of what predominates the electrical literature, a good physics book will tell you that Ohm's law is an electrical property of a material, specifically its electrical linearity. I can provide documentation for that statement if necessary.
So V=I*R is correct, but it is not Ohm's law. It is a definition. R is defined by the amount of current present at a specific voltage (R=V/I). Voltage is the electrical energy density of the charge (joules/coulomb). If V volts are lost to move Q coulombs of charge, then the energy expended is E=V*Q. Power is rate of energy and current is rate of charge. Dividing both sides of E=V*Q by t gives P=V*I.
Ratch