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Grade 12th passMechanics

A wire extends by 1mm when a force is applied. Double the force is applied to another wire of the same material and length but half the radius of cross section. The elongation of the wire in mm will be.A) 8B) 4C)2D)1

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Profile image of Praveen Chaudhary
8 Years agoGrade 12th pass
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1 Answer

Profile image of Arun
8 Years ago
Dear Praveen
 
As we know
 
l proportional to F/r²
 
Hence
 
l2/l1 = F2* (r1)²/F1* (r2)²
 = 2 * 2² = 8
 
l2 = 8 l1 = 8 * 1 = 8mm