Volume of a Sphere = ${4/3}πr^3$
where $r$ is the radius of the sphere .
Volume of a Hemisphere = ${2/3}πr^3$
where $r$ is the radius of the hemisphere .
Assume π = $22/7$ unless stated otherwise
1. Find the volume of a sphere whose radius is (i) 7 cm (ii) 0.63 m 2. Find the amount of water displaced by a solid spherical ball of diameter (i) 28 cm (ii) 0.21 m 3. The diameter of a metallic ball is 4.2 cm. What is the mass of the ball, if the density of the metal is 8.9 g per $cm^3$? 4. The diameter of the moon is approximately one-fourth of the diameter of the earth. What fraction of the volume of the earth is the volume of the moon? 5. How many litres of milk can a hemispherical bowl of diameter 10.5 cm hold? 6. A hemispherical tank is made up of an iron sheet 1 cm thick. If the inner radius is 1 m, then find the volume of the iron used to make the tank. 7. Find the volume of a sphere whose surface area is 154 $cm^2$. 8. A dome of a building is in the form of a hemisphere. From inside, it was white-washed at the cost of ₹ 4989.60. If the cost of white-washing is ₹ 20 per square metre, find the (i) inside surface area of the dome, (ii) volume of the air inside the dome. 9. Twenty seven solid iron spheres, each of radius r and surface area S are melted to form a sphere with surface area S'. Find the (i) radius r' of the new sphere, (ii) ratio of S and S'. 10. A capsule of medicine is in the shape of a sphere of diameter 3.5 mm. How much medicine (in $mm^3$) is needed to fill this capsule?