An iron rod with diameter 4 cm and length 12 cm is drawn into a wire of length 12 m of uniform thickness. Determine the thickness of the wire.

0.4 cm

We have,

Length of the rod (h) = 12 cm

Diameter of the rod = 4 cm

then the radius (R) = 2 cm

Length of the wire (H) = 12 m

According to question,

Volume of rod = Volume of wire

=π(R)²H = πr²h

=r² = (2)² × \(\frac{12}{1200}\)

=r² = 0.04

= r = \(\sqrt {0.04}\) = 0.2

Thickness= diameter= 2 × 0.2 = 0.4 cm