The area of the base of a cylinder is $20 \, cm^{2}$ and its height is $5 \, cm$. Then,its volume is $\ldots \ldots \ldots \, cm^{3}$.

Write 'True' or 'False' and justify your answer:
The actual capacity of a vessel as shown in the figure is equal to the difference between the volume of the cylinder and the volume of the hemisphere.

$A$ solid iron cuboidal block of dimensions $4.4 \, m \times 2.6 \, m \times 1 \, m$ is recast into a hollow cylindrical pipe of internal radius $30 \, cm$ and thickness $5 \, cm$. Find the length of the pipe in meters.

How many balls of radius $0.5\, cm$ can be produced by melting a metallic cylinder with radius $4\, cm$ and height $3\, cm$?

$A$ cylinder with radius $8 \, cm$ and height $9 \, cm$ is surmounted by a cone of height $15 \, cm$. Find the total surface area and the volume of the combined solid.

$A$ right circular cylinder of radius $r \, cm$ and height $h \, cm$ (where $h > 2r$) just encloses a sphere. What is the diameter of the sphere (in $cm$)?