COMEDK · Physics · 19. Current Electricity
The resistance of a wire is \(R\) ohm. If it is melted and stretched to \(n\) times its original length, its new resistance will be
- A \(n R\)
- B \(\dfrac{R}{n}\)
- C \(n^{2} R\)
- D \(\dfrac{R}{n^{2}}\)
Answer & Solution
Correct Answer
(C) \(n^{2} R\)
Step-by-step Solution
Detailed explanation
The resistance of a wire is given by \(R = \rho \dfrac{l}{A}\), where \(\rho\) is the resistivity, \(l\) is the length, and \(A\) is the cross-sectional area. When the wire is stretched to \(n\) times its original length, the new length becomes \(l' = nl\). Since the volume of…
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