R. D. Sharma Solutions for Chapter: Surface Area and Volume of a Sphere, Exercise 1: EXERCISE

A hemispherical bowl made of brass has inner diameter $10.5 \mathrm{cm}$. Find the cost of tin-plating it on the inside at the rate of $₹ 4$ per $100 {\mathrm{cm}}^2$.

The dome of a building is in the form of a hemisphere. Its radius is $63 \mathrm{dm}$. Find the cost of painting it at the rate of $₹ 2$ per $sq.m$.

A cylinder of same height and radius is placed on the top of a hemisphere. Find the curved surface area of the shape if the length of the shape be $7 \mathrm{cm}$. 

The diameter of the moon is approximately one fourth of the diameter of the earth. Find the ratio of their surfcae areas.

A hemi-spherical dome of a building needs to be painted. If the circumference of the base of the dome is $17.6 \mathrm{m}$, find the cost of painting it, given the cost of painting is $₹ 5$ per $100 {\mathrm{cm}}^2$.

A wooden toy is in the form of cone surrmounted on a hemisphere. The diameter of the base of the cone is $16 cm$ and its height is $15 \mathrm{cm}$. Find the cost of painting the toy at Rs.$7$ per $100 {\mathrm{cm}}^2$.

A storage tank consists of a circular cylinder with a hemisphere adjoined on either end. If the external diameter of the cylinder be $1.4 \mathrm{m}$ and its length be $8 \mathrm{m}$, find the cost of painting it on the outside at the rate of $₹10 \mathrm{per} {\mathrm{m}}^2$.

The front compound wall of a house is decorated by wooden spheres of diameter $21 \mathrm{cm}$ placed on small supports as shown in Fig. Eight such spheres are used for this purpose, and are to be painted silver. Each support is a cylinder of radius $1.5 \mathrm{cm}$ and height $7 \mathrm{cm}$ and is to be painted black. Find the cost of paint required if silver paint costs $25$ paise per ${\mathrm{cm}}^2$ and black paint costs $5$ paise per ${\mathrm{cm}}^2$.