A metal wire of length l and diameter d has a resistance R. What would be the resistance of another wire of the same metal and of same length but having double the diameter?
- A. R
- B. R/4 ✓
- C. R/2
- D. 2R
Correct Answer: B. R/4
Explanation
Resistance R is inversely proportional to the cross-sectional area (A = \frac{\pi d^2}{4}). If the diameter d is doubled, the area increases by a factor of 4, meaning the new resistance becomes R/4.
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