(c) 1200 π cm, 426.24 π2 gm
One round of wire covers 4 mm = \(\frac4{10}\) cm in thickness of the surface of the cylinder
Length of the cylinder = 24 cm
∴ Number of rounds to cover 24 cm = \(\frac{24}{\frac4{10}}=\frac{24\times10}{4}=60\)
Diameter of the cylinder = 20 cm
⇒ Radius of cylinder = 10 cm
Length of the wire in completing one round
= 2πr = 2π x 10 cm = 20 π cm.
∴ Length of the wire in covering the whole surface
= Length of the wire in completing 60 rounds
= (20 π × 60) cm = 1200 π cm.
Radius of copper wire = 2 mm = \(\frac2{10}\) cm
∴ Volume of wire = \(\big(π\times\frac2{10}\times\frac2{10}\times1200π\big)\)cm3 = 48 π2 cm3
So, weight of wire = (48π2 × 8.88) gm = 426.24 π2 gm.