Question

a copper rod of 1 cm diameter and 8 cm length is drawn into a wire of uniform diameter and 18 m length. find the radius of the wire in cm ..
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Answer 1

Answer:

Step-by-step explanation

The volume of the rod = π×( 21​ ) 2 ×8=2π cm 3 The length of the new wire of the same volume = 18 m = 1800 cm If r is the radius ( in cm ) of cross-section of the wire, its volume = π×sr 2 ×1800 cm 3 Therefore,π×r 2 ×1800=2πr 2 = 9001​ r= 301​ So, the diameter of the cross section, i.e., the thickness of the wire is 151​ cm, i.e., 0.67 mm (approx.)