Insulation resistance of a cable of length 20 km is 2 MΩ. What will be the insulation resistance of the same cable but for a length of 200 km?
- A. 2 MΩ
- B. 20 MΩ
- C. 0.2 MΩ
- D. 200 MΩ
Answer: C. 0.2 MΩ
Explanation: Cable insulation resistance is inversely proportional to length (R_ins ∝ 1/l): R2 = R1 × (l1/l2) = 2 MΩ × (20/200) = 0.2 MΩ.