Ohm’s law is not applicable to semiconductors.
Ohm’s law states that the current through a conductor is directly proportional to the voltage across it, and inversely proportional to the resistance of the conductor. This law is only applicable to materials that obey Ohm’s law, which are called ohmic materials. Semiconductors are not ohmic materials, and therefore Ohm’s law does not apply to them.
Semiconductors are materials that have electrical conductivity between that of a conductor and an insulator. They are used in a wide variety of electronic devices, such as transistors, diodes, and solar cells. The electrical conductivity of semiconductors is affected by temperature, light, and other factors. This means that the current through a semiconductor is not directly proportional to the voltage across it, and Ohm’s law does not apply.
In contrast, conductors and insulators are ohmic materials. The current through a conductor is directly proportional to the voltage across it, and the current through an insulator is zero. This means that Ohm’s law applies to conductors and insulators.
Therefore, the correct answer to the question “Ohm’s law is not applicable to” is A. Semiconductors.