OHM’S LAW:
Ohm's law states that current through a conductor between 2 points is directly proportional to potential difference or voltage across the 2 points, and inversely proportional to the resistance between them that is
V=IR
Here V is the potential difference measured across the resistance in the units of volts; I is the current through the resistance in units of amperes and R is the resistance of the conductor having unit of ohms. More specifically, Ohm's law states that R in this relation is constant and independent of the Current.
The law was named after the German physicist Georg Ohm, who described the measurements of applied voltage and current through simple electrical circuits containing various lengths of wire.
Temperature effects:
Ohm's law has sometimes been stated as, "for a conductor in a given state, the electromotive force is proportional to the current produced.
“That is, that the resistance, the ratio of the applied electromotive force to the current, does not vary with the current strength. The qualifier in the given state is usually interpreted as meaning at a constant temperature, since the resistively of materials is usually temperature dependent.
Question:
Emf source of 6.0V is connected to a resistive lamp and a current of 2.0 amperes flows. All wires are resistance-free. What is resistance of the lamp?
1. Where in the circuit does gain in potential energy occur? Where in the circuit does loss of potential energy occur? What is Ohm's Law?
Solution:
The gain of potential energy occurs as a charge passes through battery, which means that, it gains a potential of = 6.0V. No energy is lost to the wires, as they are supposed to be resistance-free. By the conservation of energy, potential that was gained (that is =V=6.0V) should be lost in the resistor. Therefore, by Ohm's Law we get the following result:
V = I R
R=V/I
R = 3.0