Question

A cylindrical pencil sharpened at one edge is the combination of :

• A. A Cone and a Cylinder
• B. Frustum of a Cone and a Cylinder
• C. A Hemisphere and a Cylinder
• D. Two Cylinders

Hint:

Identify the characteristic geometric features of the object:
A uniform shaft represents a cylinder.
A sharp pointed tip represents a cone.
Thus, the combination is a cylinder and a cone.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
This question belongs to the topic of Solid Geometry (Mensuration).
We are asked to identify the constituent 3D shapes that form a standard sharpened pencil.

Step 2: Key Formula or Approach:
Visualizing the components of the object:
1. The main unsharpened length of the pencil is a long uniform cylinder.
2. The sharp, pointed tip used for writing is a conical surface tapering to a point.

Step 3: Detailed Explanation:
A standard pencil starts as a cylinder of uniform circular cross-section.
When one end is sharpened, wood is shaved off symmetrically to form a pointed end.
This pointed tip has a flat circular base joining the body and tapers down to a single vertex.
Geometrically, this shape is a right circular cone.
Therefore, the total shape is the union of a right circular cylinder and a right circular cone sharing a common base.

Step 4: Final Answer:
A cylindrical pencil sharpened at one edge is a combination of a cone and a cylinder.