WBJEE · Physics · Current Electricity
\(A\) metal wire of circular cross-section has a n'sistance \(R_{1}\). The wire is now stretched without breaking, so that its length is doubled and the density is assumed to remain the same. If the resistance of the wire now beromes \(R_{2},\) then \(R_{2}: R_{1}\) is
- A \(1: 1\)
- B \(1: 2\)
- C \(4: 1\)
- D \(1: 4\)
Answer & Solution
Correct Answer
(C) \(4: 1\)
Step-by-step Solution
Detailed explanation
As we know that, \(R_{1}=\rho \frac{1}{a}=\rho \frac{l^{2}}{V}\) where, \(1=\) length of wire \(a=\) area of cross-section of the wire and \(V=\) volume of the wire \(R_{1} \propto l^{2}\)…
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