Surface area & volume: IGCSE Mathematics questions with answers
Free Surface area & volume questions for IGCSE Mathematics (0580), part of Mensuration. Each question has the answer and the marking points an examiner would look for.
A cylindrical tank of radius 10 cm contains water to a depth of 12 cm. A solid metal sphere of radius 6 cm is placed in the tank and is completely covered by the water. Calculate the new depth of the water. [The volume, V, of a sphere with radius r is V = 43πr3.]
A cylindrical tank has internal radius 6 cm and stands on a horizontal floor. It contains water to a depth of h cm. A solid ball of radius r cm, where 0 < r ≤ 6, is placed in the tank and rests on the bottom. The water level rises and the ball is then exactly covered: the water surface just touches the top of the ball. No water is lost. [Volume of a sphere = 43πr3]
(a)
For some values of h, only one size of ball can be exactly covered. Find the set of these values of h. Give any boundary values exactly.
[9]
(b)
A ball of radius 3 cm is exactly covered. The ball is removed, the water level returns to its original depth, and a ball of a different radius is placed in the tank. This ball is also exactly covered. Find the radius of the second ball.
[4]
Show answers and mark scheme
Part
Answer and marking points
Marks
(a)
0 < h < 4 or h = 4√2
water + ball fill a cylinder of height 2r: 36π × 2r = 36πh + 43πr3M1 h = 2r − r327A1 dhdr = 2 − r29 = 0 M1 r = 3√2 (≤ 6), maximum h = 6√2 − 2√2 = 4√2 A1 at r = 6 (largest ball that fits), h = 12 − 8 = 4 B1 h rises from 0 to 4√2 for 0 < r ≤ 3√2 and falls from 4√2 to 4 for 3√2 ≤ r ≤ 6 M1 so 4 ≤ h < 4√2 gives two radii (h = 4: r = 6 and r = 3√3 − 3) M1 0 < h < 4 A1 or h = 4√2 A1
Riyaz Shaikh has mentored IGCSE, IB and A Level students for 15+ years, one-on-one, online and in Mumbai. The hardest questions on this site are the ones he uses to find a student's weak points.
Original Cambridge-style practice questions written for mentorriyaz.in. These are not Cambridge past paper questions, and this site is not affiliated with or endorsed by Cambridge University Press & Assessment. Updated 2026-11-04. Paper generator · mentorriyaz.in