Ohm's Law

Ohm's Law is a fundamental relationship in electrical circuits, where the current through a conductor is directly proportional to the voltage applied across it, with the proportionality constant being the resistance of the conductor.

The unit of resistance in the SI system is the Ohm (Ω), named after the German physicist Georg Ohm. It represents the resistance offered by a conductor to the flow of electric current.

According to Ohm's Law, the current through a conductor is directly proportional to the voltage applied across it. Therefore, if the voltage is doubled while the resistance remains constant, the current will also double.

Ohm's Law states that the current through a conductor is inversely proportional to the resistance. Therefore, if the resistance is increased while the voltage remains constant, the current will decrease.

Using Ohm's Law (I = V / R), we can calculate the current: I = 12 V / 10 Ω = 1.2 A.

In a series circuit, the total resistance is the sum of the individual resistances of the components connected in series.

In a parallel circuit, the total resistance is the reciprocal of the sum of the individual resistances of the components connected in parallel.

The power dissipated in a resistor is given by the formula P = I^2 * R, where P is the power in watts, I is the current in amperes, and R is the resistance in ohms.

Using the formula P = V^2 / R, we can calculate the power: P = (120 V)^2 / 100 Ω = 144 W.

For most conductors, the resistance increases as the temperature increases. This is because the increased thermal energy causes the atoms in the conductor to vibrate more, which hinders the flow of electrons.

Superconductors are materials that exhibit zero resistance, meaning they allow electric current to flow through them without any energy loss.

Heike Kamerlingh Onnes, a Dutch physicist, first discovered superconductivity in 1911 while studying the electrical resistance of mercury at very low temperatures.

Superconductivity is a quantum phenomenon that occurs at very low temperatures, typically near absolute zero (-273.15 °C or -459.67 °F).

Superconductors have a wide range of applications, including power transmission with reduced losses, medical imaging (MRI), and magnetic levitation trains (maglev).

The critical temperature (Tc) of a superconductor is the temperature above which it loses its superconducting properties and starts behaving like a normal conductor.