A cylindrical metallic rod of diameter 2 cm and length 45 cm is melted and converted into wire of uniform thickness and length 5 m. The diameter of the wire is:
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 6 mm
Given:
Diameter cylindrical metallic rod = 2 cm
Height of cylindrical metallic rod = 45 cm
Height of wire = 5 m or 500 cm
Volume of cylinder = πr2h
Where r and h are the radius and height of the cylinder
Let the radius of the wire be x.
According to the question;
⇒ π × 12 × 45 = π × x2 × 500
⇒ x2 = 9/100
⇒ x = 0.3 cm or 3 mm
Diameter = 2x = 2 × 3 = 6 mm