Write 'True' or 'False' and justify your answer:
Two identical solid cubes of side $a$ are joined end to end. Then the total surface area of the resulting cuboid is $12 a^{2}$.

The rainwater from a roof of dimensions $22 \, m \times 20 \, m$ drains into a cylindrical vessel having a base diameter of $2 \, m$ and a height of $3.5 \, m$. If the rainwater collected from the roof just fills the cylindrical vessel,find the rainfall in $cm$.

$A$ factory manufactures $120000$ pencils daily. The pencils are cylindrical in shape,each of length $25 \,cm$ and circumference of base $1.5 \,cm$. Determine the cost of colouring the curved surfaces of the pencils manufactured in one day at $\operatorname{Rs.} 0.05$ per $dm^2$ (in $Rs.$).

$16$ glass spheres,each of radius $2 \,cm$,are packed into a cuboidal box of internal dimensions $16 \,cm \times 8 \,cm \times 8 \,cm$. The box is then filled with water. Find the volume of water filled in the box (in $cm^3$).

The radius and height of a cone are $5\,cm$ and $12\,cm$ respectively. Then,the ratio of its $CSA$ and area of base is $\ldots \ldots \ldots \ldots$

The volume of a sphere with diameter $10 \, cm$ is $\ldots \ldots \, cm^3$.