Solution: For copper wire: Diameter = 3 mm = 0.3 cm
For cylinder; length h = 12 cm, d = 10 cm
Density of copper = 8.88 gm cm3
Curved surface area of cylinder can be calculated as follows:

Length of wire can be calculated as follows:

Now, volume of wire can be calculated as follows:

Mass can be calculated as follows:
Mass = Density × Volume
= 8.88 × 88.7364
= 788 g (approx)