Volume: 64×34πr3=34πR3, so R3=64r3, giving R=4r. Ratio S′:S=4πR2:4πr2⋅64? No, S is surface of one small sphere. S′=4πR2=4π(4r)2=64πr2. S=4πr2. Ratio =64:4=16:1.
Note: The chosen option 1 (4:1) is incorrect; the correct answer is option 3 (16:1).
CUET UG 2023 — General Test Geometry
64 small solid iron spheres of radius 'r' are melted to form a big sphere of radius R. If S and S' are surface areas of the small and the big sphere respectively, then find the ratio S' : S.
Held on 28 May 2023 · Verified 13 Jul 2026.
4 : 1
8 : 1
16 : 1
24 : 1
Sign in to track your attempts and accuracy.
Sign in to keep a private note on this question. Nothing you write is ever public.
Match the given areas of various solid objects with their respective formulae: | List I | List II | |---|---| | Area of solid object | Formula | | (A) Lateral surface area of a cylinder | (I) $\pi r\sqrt{r^2 + h^2}$ | | (B) Total surface area of a hemisphere | (II) $4\pi r^2$ | | (C) Lateral surface area of a cone | (III) $2\pi rh$ | | (D) Surface area of a sphere | (IV) $3\pi r^2$ | (Where, r = radius of the solid shape (or base) and h = height of the solid shape.) Choose the correct answer from the options given below:
A solid, metallic right circular cone of radius 7 cm and height 3 cm is melted into three cubes. If the sides of two cubes are 3 cm and 5 cm, then the side of the third cube will be how much?
The area of a rectangle whose length is 5 more than twice its width is 75 square unit. What is the perimeter of the rectangle?
(A). The angles of depression of two ships from the top of a lighthouse are $60^\circ$ and $45^\circ$ towards the east. If the ships are $300$ meter apart, the height of the lighthouse is $150(3+\sqrt{3})$ $$\newline$ (B). If the surface area of a cube is $726 \text{ m}^2$, then its volume shall be $1331 \text{ m}^3$ $$\newline$ (C) If the ratio of diameters of two spheres is $3:5$, then the ratio of their surface area shall be $9:25$ $$\newline$$ Determine as to which of the statements given above are correct :
If area of a square is 44 cm², find the area of the circle formed by the same perimeter.
Work through every CUET UG Geometry PYQ, year by year.