The volume of two spheres are in the ratio 27 : 125. The ratio of thei...
Option 4 : 9 : 25
Given
Ratio of volume of two spheres = 27 : 125
Formula used
surface area of sphere =4πr2
Volume of sphere = (4/3)πr3
Where r is radius respectively
Calculation
[(4/3)πR3/(4/3)πr3] = 27/125
Where R and r are radius of two sphere
⇒ R3/r3= 27/125
⇒ R = 3r/5
Surface area of 1st sphere/Surface area of 2nd sphere =[4π(3r/5)2]/4πr2
⇒ 9 : 25
∴ Ratio of surface area of two spheres is 9 : 25.
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The volume of two spheres are in the ratio 27 : 125. The ratio of thei...
Given, the weight of two spheres made of the same material are 3.6 kg and 2.7 kg and the radius of the smaller sphere is 2 cm.
Let the radius of the larger sphere be 'r'.
We know that the volume of a sphere is proportional to the cube of its radius. Therefore,
(Volume of smaller sphere) / (Volume of larger sphere) = (r_small)^3 / (r_large)^3
We also know that the spheres are made of the same material. Therefore, their densities are the same.
Density = Mass / Volume
Mass = Density x Volume
Therefore, the masses of the two spheres are proportional to their volumes.
(Mass of smaller sphere) / (Mass of larger sphere) = (Volume of smaller sphere) / (Volume of larger sphere)
Given, the masses of the two spheres are 3.6 kg and 2.7 kg.
Therefore, (Mass of smaller sphere) / (Mass of larger sphere) = 3.6 / 2.7 = 4 / 3
Using the above two equations, we get:
(r_small)^3 / (r_large)^3 = 4 / 3
(2)^3 / (r_large)^3 = 4 / 3
(r_large)^3 = (2)^3 x (3/4) = 27/2
r_large = (27/2)^(1/3) ≈ 2.6 cm
Therefore, the radius of the larger sphere is approximately 2.6 cm. Hence, option 'D' is the correct answer.