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)πr3
Volume of cylinder = πr2h
Calculation
(4/3) × π × r3 = π × R2 × 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.