AExE01 · Chapter 1Basic Electrical & Electronics🏛️ Past Licensure QuestionID: fa7db0f9
Two wires of the same length and material are tested. One wire has a resistance of 40 Ω. If a second wire has a cross-sectional area n times that of the first, its resistance is:
Two wires of the same length and material are tested. One wire has a resistance of 40 Ω. If a second wire has a cross-sectional area n times that of the first, its resistance is:
Multiple Choice Options
- A
40n Ω
- B✓ Correct Option
40/n Ω
- C
40n^2 Ω
- D
40/n^2 Ω
Detailed Technical Solution & Explanation
Resistance is inversely proportional to cross-sectional area: . For two wires of identical length and material, if wire 1 has area and resistance , a second wire having an area times larger () will have a resistance reduced by a factor of : .
Option Analysis:
•
Option A (40n Ω): Incorrect. Resistance decreases with area, not increases.
•
Option B (40/n Ω): Correct. Resistance is inversely proportional to the area scaling factor .
•
Option C (40n^2 Ω): Incorrect.
•
Option D (40/n^2 Ω): Incorrect.
Reference: Demo2 · Set 2NEC Licensure Syllabus