Surface area

Asked by Abhijeetoo7 | 19th Feb, 2010, 11:37: AM

Expert Answer:

Let's imagine the cylinder the hollow and we cut it open.

Now it's like a rectangle, with width = circumference, and length = length of the cylinder.

One wrap or turn of the copper wire covers an are of widthxdiameter of copper wire = 2πRxd =

2x3.14x 50 mmx 3 mm = 942 mm2.

So a length of 2πR = 2x3.14x 50 mm = 314 mm of copper wire covers an area of 942 mm2

Curved surface of cylinder = 2 x 3.14 x 50 mm x 120 mm = 37680 mm2

length of copper wire, = 37680x 314/942 =  12560 mm = 1256 cm

Volume of wire = πd2L/4 = 3.14x0.09x1256/4 = 88.74 cm3

Mass of wire = density x volume = 8.88x88.74 = 788.01 gm = 0.788 kg.

Hence,

Length of copper wire = 1256 cm.

Mass of copper wire = 0.788 kg.

Regards,

Team,

TopperLearning.

Answered by  | 19th Feb, 2010, 03:06: PM

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