Q31 of 70 Page 19

Find the length of 13.2 kg copper wire of diameter 4 mm, when 1 cubic cm of copper weighs 8.4 gm.


Given,


Weight of copper wire = 13.2 kg = (13.2×1000) gm


Diameter of wire = 4mm


So, radius of wire =


Weight of 1 cm3 wire = 8.4 gm


Let length of wire = h cm


So, volume ×8.4 = 13.2×1000


= πr2h×8.4 = 13.2×1000


=


= h =


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