A rod of 2 cm diameter and 30 cm length is converted into

Home » Aptitude » Volume and Surface Area of Solid Figures » Question

A rod of 2 cm diameter and 30 cm length is converted into a wire of 3 cm length of uniform thickness. The diameter of the wire is ?

1. 2/10 cm
2. 2/√10 cm
3. 1/√10 cm
4. 1/10 cm

Correct Option: B

Given, r₁ = 1 cm, h₁ = 30 cm, h₂ = 300 cm.
Volume of rod = Volume of wire
⇒ πr₁²h₁ = πr²₂h₂
⇒ π x (1)² x 30 = π x r²₂ x 300
⇒ r²₂ = 30/300
∴ r₂ = 1/√10 cm
∴ diameter = 2r₂
= 2 x 1/√10 = 2/√10cm.