AP Physics 2mediummcq1 pt
A wire has a resistance of 5Ω. If the wire is stretched to twice its original length while maintaining the same volume, what will be its new resistance?
A.5 Ω
B.10 Ω
C.20 Ω
D.40 Ω
Explanation
Core Concept
When the wire is stretched to twice its original length, its cross-sectional area decreases by half to maintain the same volume. Since resistance is proportional to length and inversely proportional to cross-sectional area, R = ρL/A, doubling the length and halving the area results in a resistance that is 2 × 2 = 4 times the original resistance. Therefore, the new resistance is 4 × 5Ω = 20Ω.
Correct Answer
C20 Ω
More Unit 4: Electric Circuits practice questions
- easyA capacitor is fully charged in an RC circuit. Which statement is true?
- easyIn the loop rule, a resistor traversed in the current's direction contributes
- easyA 20 Ω resistor with 2.0 A flowing dissipates
- easyWhich configuration doubles the total resistance of a circuit with one resistor R?
- easyA circuit with two identical resistors in series across 10 V has what voltage across each?
Practice more AP Physics 2 questions with full explanations
Practice Unit 4: Electric Circuits Questions →