Correct Answer - Option 3 : 14/27 cm

**Given**

Diameter of sphere= 7 cm

Diameter of wire = 21 cm

**Formula used**

Volume of sphere = (4/3)πr^{3}

Volume of cylinder = πr^{2}h

**Calculation**

(4/3) × π × r^{3 }= π × R^{2} × h

Where r is the radius of the sphere, R and h are the radius and height of the cylinder.

⇒ (4/3) × (7/2) × (7/2) × (7/2) = (21/2) × (21/2) × h

⇒ (2 × 7 × 7 × 7)/(3 × 21 × 21) = h

⇒ 14/27 = h

**∴ The length of a wire is 14/27 cm.**