JEE Mains · Physics · STD 12 - 3. current electricity
A wire of \(1 \,\Omega\) has a length of \(1\, m\). It is stetched till its length increases by \(25\, \%\). The percentage change in resistance to the neartest integer is .....\(\%\)
- A \(56\)
- B \(25\)
- C \(12.5\)
- D \(76\)
Answer & Solution
Correct Answer
(A) \(56\)
Step-by-step Solution
Detailed explanation
\(R _{0}=1\, \Omega\) \(\ell_{0}=1\, m\) \(A _{0}= A\) \(R _{1}=?\) \(\ell_{1}=1.25\, m\) As volume of wire remains constant so \(A _{0} \ell_{0}= A _{1} \ell_{1} \Rightarrow A _{1}=\frac{\ell_{0} A _{0}}{\ell_{1}}\) Now Resistance \(( R )=\frac{\rho \ell}{ A }\)…
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