Page 2 - Lesson Note-4-Ch-13 SA and Volume(Sphere)

1. Area of base = r sq .unit
2
2. Curved Surface Area (CSA) 2 r sq= 2 .unit
3. Total Surface Area (TSA) = +
2
= + 2 = 3 sq. unit
2
2
2
3
4. Volume of a hemisphere = cubic unit
3
Hollow Sphere

A hollow sphere is a ball that has been hollowed such that an equal thickness of wall
creates another internal ball within the external ball.

Surface Area of a hollow Sphere and Hemi sphere

Let the External radius be ‘R’ and Internal radius be ‘r’

1. Surface Area of a hollow sphere =
+
2
2
=4 + 4
= 4 ( + ) sq. unit
2
2
2. Volume of a Hollow Sphere = −
4
3
= ( − ) cubic unit
3
3
2
3. Area of base of hollow hemi-sphere (Area of Ring)= ( − ) sq. unit
2
4. Curved Surface Area of hollow hemi-sphere (CSA)= +
=2 + 2
2
2
= 2 ( + ) sq. unit
2
2
2