A copper wire of radius r and length l has a resistance of R. A second copper wire with radius 2r and length l is taken and the two wires are joined in a parallel combination. The resultant resistance of the parallel combination of the two wires will be

A copper wire of radius r and length l has a resistance of R. A second

1.	A copper wire of radius r and length l has a resistance of R. A second copper wire with radius 2r and length l is taken and the two wires are joined in a parallel combination. The resultant resistance of the parallel combination of the two wires will be
Answer» <html><body><p><<a href="https://interviewquestions.tuteehub.com/tag/p-588962" style="font-weight:bold;" target="_blank" title="Click to know more about P">P</a>> <a href="https://interviewquestions.tuteehub.com/tag/r-611811" style="font-weight:bold;" target="_blank" title="Click to know more about R">R</a>/5</p><br/><br/><p>1st copper wire: R = <a href="https://interviewquestions.tuteehub.com/tag/pl-591629" style="font-weight:bold;" target="_blank" title="Click to know more about PL">PL</a>/A = pl/ πr2<br/>2ndcopper wire: R’ = p’<a href="https://interviewquestions.tuteehub.com/tag/l-535906" style="font-weight:bold;" target="_blank" title="Click to know more about L">L</a>’/A’ = pl/(4 πr2) = R/4<br/>If <a href="https://interviewquestions.tuteehub.com/tag/joined-521893" style="font-weight:bold;" target="_blank" title="Click to know more about JOINED">JOINED</a> in parallel, (1/Req) = (1/R) + (1/R’)<br/>= 1/R + 4/R<br/>= 5/R<br/>Req = R/5</p></body></html>