Q : 7 A lead pencil consists of a cylinder of wood with a solid cylinder of graphite filled in the interior. The diameter of the pencil is 7 mm and the diameter of the graphite is 1 mm. If the length of the pencil is 14 cm, find the volume of the wood and that of the graphite.
Length of the cylindrical pencil =
The radius of the graphite (Inner solid cylinder) =
Radius of the pencil (Inner solid graphite cylinder + Hollow wooden cylinder) =
We know, Volume of a cylinder=
The volume of graphite =
And, Volume of wood =
Therefore, the volume of wood is and the volume of graphite is