Question

Find the length of 22 kg copper wire of diameter 0.8 cm, if the weight of 1 cm³ copper is 4.2 g.

Answer 1

Diameter of the wire = 0.8cm
Radius of the wire = 0.4cm
If 4.2g of copper = 1cm³ of copper

Then 22kg copper = `(220000)/(4.2)"cm"^3`
Volume of the copper wire = Area of base x length of wire

`(22000)/(4.2)` = πr² x h

`(22000)/(4.2) = (22)/(7) xx 0.4^2 xx "h"`

h = `(22000 xx 7)/(4.2 xx 22 xx 0.4 xx 0.4)`
h = 10416.7cm
∴ h = 104.17m
∴ The length of the copper wire is 104.17m.