The correct Answer is R ∝ l and R ∝ 1/A
Explanation
The resistance of a metallic conductor is a measure of its opposition to the flow of electric current. This property depends on the material of the conductor and its physical dimensions.
Statement-wise Analysis
- R ∝ l and R ∝ A
Incorrect. Resistance is directly proportional to the length (l) of the conductor, but it is inversely proportional to its cross-sectional area (A). Therefore, this statement is incorrect.
- R ∝ 1/l and R ∝ 1/A
Incorrect. Resistance is directly proportional to the length (l), not inversely proportional. It is inversely proportional to the cross-sectional area (A). Therefore, this statement is incorrect.
- R ∝ l and R ∝ 1/A
Correct. The resistance (R) of a uniform metallic conductor is directly proportional to its length (l) and inversely proportional to its cross-sectional area (A). This relationship is expressed by the formula R = ρ(l/A), where ρ (rho) is the resistivity of the material.
- R ∝ 1/l and R ∝ A
Incorrect. Resistance is directly proportional to the length (l), not inversely proportional. It is inversely proportional to the cross-sectional area (A), not directly proportional. Therefore, this statement is incorrect.
Key Takeaway
The resistance of a uniform metallic conductor is directly proportional to its length and inversely proportional to its cross-sectional area.