Question

The current in a conductor is directly proportional to the potential difference between its ends. This is called____

• A. Faraday's law
• B. Kirchoff's law
• C. Ohm's law
• D. Newton's law

Answer 1

The Correct Option is C

To solve the problem, we need to identify the law that states the current in a conductor is directly proportional to the potential difference between its ends.

1. Understanding the Statement:
The given statement describes a fundamental relationship in electricity: the current flowing through a conductor is directly proportional to the potential difference (voltage) applied across it, provided the temperature and other physical conditions remain constant.

2. Analyzing the Options:

(A) Faraday's Law: This law deals with electromagnetic induction, specifically the production of an electromotive force (EMF) in a conductor due to a changing magnetic field. It does not describe the relationship between current and voltage.
 
(B) Kirchhoff's Law: These laws are used to analyze complex circuits and consist of two parts:
 - Kirchhoff's Current Law (KCL): The sum of currents entering a junction equals the sum of currents leaving the junction.
 - Kirchhoff's Voltage Law (KVL): The sum of voltages around any closed loop in a circuit is zero.
 Neither part of Kirchhoff's laws directly relates to the proportionality between current and voltage.

(C) Ohm's Law: This law states that the current \( I \) 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. Mathematically, it is expressed as:
 \(V = I \cdot R\)
 or equivalently,
\(I \propto V \quad \text{(when } R \text{ is constant)}.\)
 This directly matches the statement in the question.

(D) Newton's Law: These laws describe the motion of objects under the influence of forces and do not relate to electrical phenomena.

3. Conclusion:
The correct answer is Ohm's Law, as it explicitly states the direct proportionality between current and voltage in a conductor.

Final Answer: (C) Ohm's law.