$A$ 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 $cm$)?

The radius and height of a cylinder are $1.4 \, cm$ and $10 \, cm$ respectively. Then,its curved surface area is $\ldots \ldots \ldots \, cm^2$.

$CSA$ of a cylindrical tank with diameter $2.1 \, m$ and height $5 \, m$ is $\ldots \ldots \ldots \ldots \, m^2$.

The base of a cone with radius $7\, cm$ and height $24\, cm$ is hemispherical. Find the cost of painting its surface at the rate of ₹ $2/cm^2$. (in ₹)

Write 'True' or 'False' and justify your answer:
Total surface area of a lattu (top) as shown in the $Fig.$ is the sum of total surface area of hemisphere and the total surface area of cone.

Rasheed got a playing top $(lattu)$ as his birthday present,which surprisingly had no colour on it. He wanted to colour it with his crayons. The top is shaped like a cone surmounted by a hemisphere (see figure). The entire top is $5 \, cm$ in height and the diameter of the top is $3.5 \, cm$. Find the area he has to colour (in $cm^2$). (Take $\pi = \frac{22}{7}$)