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Q : 10    A capsule of medicine is in the shape of a sphere of diameter \small 3.5\hspace{1mm}mm. How much medicine (in \small mm^3) is needed to fill this capsule?
 

Given, The radius of the spherical capsule = The volume of the capsule =  Therefore,  of medicine is needed to fill the capsule.

Q : 9    Twenty seven solid iron spheres, each of radius r and surface area S are melted to form a sphere with surface area \small S'. Find the

            (ii) ratio of S and \small S'.

Given, The radius of a small sphere =  The surface area of a small sphere =  The radius of the bigger sphere =  The surface area of the bigger sphere =  And,  We know, the surface area of a sphere =  The ratio of their surface areas =  Therefore, the required ratio is     

Q : 9    Twenty seven solid iron spheres, each of radius r and surface area S are melted to form a sphere with surface area \small S'. Find the

            (i) radius \small r' of the new sphere

Given, The radius of a small sphere =  The radius of the bigger sphere =  The volume of each small sphere=  And, Volume of the big sphere of radius =  According to question,

Q : 8    A dome of a building is in the form of a hemisphere. From inside, it was white-washed at the cost of \small Rs\hspace{1mm}4989.60. If the cost of white-washing is Rs 20 per square metre, find the

(ii) volume of the air inside the dome. 

Let the radius of the hemisphere be  Inside the surface area of the dome =  We know, Surface area of a hemisphere =    The volume of the hemisphere = 

Q : 8    A dome of a building is in the form of a hemisphere. From inside, it was white-washed at the cost of \small Rs\hspace{1mm}4989.60. If the cost of white-washing is Rs 20 per square metre, find the

            (i) inside surface area of the dome

Given,  is the cost of white-washing  of the inside area  is the cost of white-washing  of inside area (i) Therefore, the surface area of the inside of the dome is       

Q : 7     Find the volume of a sphere whose surface area is \small 154\hspace{1mm}cm^2.

Given, The surface area of the sphere =  We know, Surface area of a sphere =    The volume of the sphere = 

Q : 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. 

Given, Inner radius of the hemispherical tank =  Thickness of the tank =   Outer radius = Internal radius + thickness =  We know, Volume of a hemisphere =   Volume of the iron used = Outer volume - Inner volume 

Q : 5    How many litres of milk can a hemispherical bowl of diameter \small 10.5\hspace{1mm}cm hold?
 

The radius of the hemispherical bowl =  We know, Volume of a hemisphere =  The volume of the given hemispherical bowl =  The capacity of the hemispherical bowl =     

Q : 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?
 

Given, Let  be the diameters of Earth  The diameter of the Moon =  We know, Volume of a sphere =    The ratio of the volumes =  Therefore, the required ratio of the volume of the moon to the  volume of the earth is 

Q : 3    The diameter of a metallic ball is \small 4.2\hspace{1mm}cm. What is the mass of the ball, if the density of the metal is \small 8.9\hspace{1mm}g per \small cm^3?
 

Given, The radius of the metallic sphere =  We know, Volume of a sphere =   The required volume of the sphere =  Now, the density of the metal is  per ,which means, Mass of  of the metallic sphere =  Mass of  of the metallic sphere = 

Q : 2    Find the amount of water displaced by a solid spherical ball of diameter

            (ii)     \small 0.21\hspace{1mm}m

The solid spherical ball will displace water equal to its volume.  Given, The radius of the sphere =  We know, Volume of a sphere =   The required volume of the sphere =  Therefore, amount of water displaced will be 

Q : 1    Find the volume of a sphere whose radius is

           (ii) \small 0.63\hspace{1mm}m

Given, The radius of the sphere =  We know, Volume of a sphere =  The required volume of the sphere = 

Q : 1    Find the volume of a sphere whose radius is

            (i) 7 cm

Given, The radius of the sphere =  We know, Volume of a sphere =  The required volume of the sphere = 
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