Q15 of 26 Page 183

Let us write whether the following statements are true of false.

i. If we double the length of radius of a solid sphere, the volume of sphere will be doubled.


ii. If the ratio of curved surface areas of two hemispheres is 4 : 9, the ratio of their lengths of radii is 2 : 3.

(i) False.


The volume of a sphere is directly proportional to the cube of the radius. So if the radius is doubled, volume becomes 8 times.


(ii) True.



Let the radius of two spheres be r1 and r2;


Ratio of surface area


⇒


⇒ r1:r2 = 2:3


More from this chapter

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15

If the ratio of curved surface areas of two solid spheres is 16 : 9, the ratio of their volumes is

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If numerical value of curved surface area of a solid sphere is three times of its volume the length of radius is

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Let us fill in the blanks.

i. The name of solid which is composed of only one surface is _______.


ii. The number of surfaces of a solid hemisphere is ___________.


iii. If the length of radius of a solid hemisphere is 2r units, its whole surface area is __________ π r2 sq units.

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The numerical values of volume and whole surface area of a solid hemisphere are equal, let us write the length of radius of the hemisphere.