A uniform metal wire of length / has $10 \Omega$ resistance. Now this wire is stretched to a length $2 /$…
A uniform metal wire of length / has $10 \Omega$ resistance. Now this wire is stretched to a length $2 /$ and then bent to form a perfect circle. The equivalent resistance across any arbitrary diameter of that circle is
$10 \Omega$
$5 \Omega$
$40 \Omega$
$20 \Omega$
Solution
$R_0=10 \Omega$
After stretching its length upto 2l
$R_1=n^2 R_0$
$=4 R_0$
$=40 \Omega$
$R_{A B}=\frac{20 \times 20}{20+20}=10 \Omega$
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