Engineering Board Exam Reviewer · Voltage, Current and Resistance · hard
A wire of resistance 4, is drawn out uniformly to twice its original length (its volume stays the same). What is its new resistance?
- 8,
- 2,
- 4,
- 16,
Answer
D. 16,
Solution
Doubling the length halves the cross-sectional area (constant volume). R= /A becomes 2L/A/2=4R=16, .
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