A cylindrical jar

Given that, radius of cylindrical jar, r = 6cm

Depth/height of the jar, h = 2cm

Volume of the jar, V’ = π r² h

⇒ V’ = π (6)² (2) cm³

Radius of the sphere = 1.5cm

So, volume of the sphere =

Volume of oil in cylindrical jar = volume of n spheres needed to raise the level by 2 cm

⇒ n = 16

∴ number of iron sphere needed = 16