JEE Mains · Physics · STD 12 - 3. current electricity
The resistance of a wire is \(5 \Omega\). It's new resistance in ohm if stretched to \(5\) times of it's original length will be :
- A \(625\)
- B \(5\)
- C \(125\)
- D \(25\)
Answer & Solution
Correct Answer
(C) \(125\)
Step-by-step Solution
Detailed explanation
\(R _{\text {initial }}=\frac{\rho \ell}{ A }=5 \Omega\) \(\because\) Volume of wire is constant in stretching \(V _{ i }= V _{ f }\) \(A _{ i } \ell_{ i }= A _{ f } \ell_{ f }\) \(A \ell= A ^{\prime}(5 \ell)\) \(A ^{\prime}=\frac{ A }{5}\)…
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