A cylinder of radius 12 cm contains water up to the height 20 cm. A spherical iron ball is dropped into the cylinder and thus water level raised by 6.75 cm. What is the radius of iron ball ?

Q.4 (2) A cylinder of radius 12 cm contains water up to the height 20 cm. A spherical iron ball is dropped into the cylinder and thus water level raised by 6.75 cm. What is the radius of iron ball ?

Doubtly Asked 25 Oct 2026 ssc 10th Save WhatsApp Report

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Answer: Radius of the iron ball = 9 cm

Volume of water displaced = volume of the sphere = rise in water level × area of the base of the cylinder.

\(V = \pi r^2 h = \pi (12)^2 (6.75) = 972\pi\) cm³.

Volume of sphere \(= \dfrac{4}{3}\pi R^3 = 972\pi\)

∴ \(R^3 = \dfrac{972 \times 3}{4} = 729\)

∴ R = 9 cm.

Doubtly AI · 25 Oct 2026 AI-verified · Oct 2026 Report

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A cylinder of radius 12 cm contains water up to the height 20 cm. A spherical iron ball is dropped into the cylinder and thus water level raised by 6.75 cm. What is the radius of iron ball ?

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