Why ohm’s law is applicable to conductors only?

Ohm’s Law is a fundamental principle in electrical engineering that establishes the relationship between voltage, current, and resistance. It states that the current (I) flowing through a conductor between two points is directly proportional to the voltage (V) across the two points and inversely proportional to the resistance (R) of the conductor, as expressed by the equation I = V / R.

This law is primarily applicable to conductors due to the nature of their electrical behavior. Conductors, often metallic in nature, possess a multitude of free electrons that can move relatively freely in response to an applied electric field. When a voltage is applied across a conductor, these free electrons experience a force that drives them in a particular direction, resulting in an electric current.

Atomic Structure and Conductivity

• In conductors, electrons are loosely bound to atoms, and they can move freely in response to an electric field.
• The ease with which electrons move in conductors leads to a linear relationship between voltage and current.

Nature of Conductivity

• Ohm’s Law is rooted in the behavior of materials with free-flowing charge carriers, such as electrons in metals.
• Conductors, by definition, facilitate the easy movement of charged particles, allowing for the application of Ohm’s Law.

The relationship defined by Ohm’s Law holds true for conductors because it is based on assumptions related to the behavior of electrons in a conductive medium. These assumptions include the idea that the conductor has a uniform and isotropic structure, the temperature remains constant, and the material exhibits linear and ohmic behavior.

Resistance in Conductors

• Ohm’s Law incorporates the concept of resistance (R), which represents the opposition to the flow of current.
• Resistance in conductors arises from collisions between moving electrons and lattice vibrations in the material.

Temperature Considerations

• Ohm’s Law assumes a constant temperature, and deviations may occur at extreme temperatures or in certain materials.
• For conductors, temperature changes can influence resistance, impacting the accuracy of Ohm’s Law in predicting electrical behavior.
• Why is ohm’s law not applicable to insulators or semiconductors?

In non-conductive materials, such as insulators or semiconductors, the behavior of electrons differs significantly. In insulators, electrons are tightly bound to atoms and do not flow freely even under the influence of an electric field. Semiconductors, while allowing some electron flow, exhibit more complex behavior and are governed by different principles, such as semiconductor physics.

Insulators and Semiconductors

• Ohm’s Law is not directly applicable to insulators and semiconductors.
• In insulators, electrons are tightly bound to atoms, hindering their movement and resulting in extremely high resistance.
• Semiconductors exhibit a more complex relationship between current and voltage, often requiring additional considerations beyond Ohm’s Law.

Ohm’s Law is applicable to conductors primarily because of the conductors’ ability to facilitate the flow of free electrons in response to an applied voltage. The unique characteristics of conductors, including their high electron mobility and ohmic behavior, make Ohm’s Law a reliable and applicable principle for analyzing electrical circuits involving metallic conductors.