Understanding Ohm's Law and its Applicability

Ohm's Law is a fundamental principle in electricity that describes the relationship between voltage, current, and resistance in an electrical circuit. It states that the voltage ($V$) across a conductor is directly proportional to the current ($I$) flowing through it, provided all physical conditions, such as temperature, remain constant. Mathematically, Ohm's Law is expressed as:

$$\text{V} = \text{I} \times \text{R}$$

Where:

• $V$ is the voltage across the conductor (in Volts)
• $I$ is the current flowing through the conductor (in Amperes)
• $R$ is the resistance of the conductor (in Ohms)

This law is applicable to materials that exhibit a linear relationship between voltage and current. Such materials are called ohmic conductors or ohmic materials. Metals like copper and aluminum are good examples of ohmic conductors under normal conditions.

Analyzing the Options

Let's look at the given options to determine which material or component obeys Ohm's Law:

• Silicon carbide: Silicon carbide (SiC) is a semiconductor material. While semiconductors can conduct electricity, their voltage-current relationship is often non-linear, especially across p-n junctions. Ohm's Law is generally not applicable to semiconductor devices over their entire operating range.
• Zener diode: A Zener diode is a specific type of semiconductor diode. Diodes are known for their non-linear current-voltage characteristics (e.g., the exponential forward bias curve and the sharp breakdown in reverse bias). Ohm's Law does not apply to a Zener diode's operation.
• Voltage regulator tubes: Voltage regulator tubes (like gas-discharge tubes) are designed to maintain a nearly constant output voltage over a range of current or input voltage. Their operating principle involves phenomena like gas ionization, which results in a non-linear voltage-current relationship. Ohm's Law is not applicable here.
• Copper: Copper is a common metal and an excellent electrical conductor. Under constant temperature and other physical conditions, copper exhibits a linear relationship between voltage and current, meaning its resistance ($R$) is constant. Therefore, Ohm's Law is applicable to copper.

Conclusion on Ohm's Law Applicability

Based on the analysis, Ohm's Law is applicable to materials that behave as ohmic conductors, showing a linear voltage-current relationship. Among the given options, copper fits this description as a metal conductor that typically obeys Ohm's Law under constant conditions.

Therefore, Ohm’s Law is applicable to copper.