Advertisements
Advertisements
प्रश्न
How many balls each of radius 1 cm can be made by melting a bigger ball whose diameter is 8 cm?
Advertisements
उत्तर
Diameter of bigger ball = 8 cm
Therefore, Radius of bigger ball = 4 cm
Volume = `4/3pir^3`
= `4/3pi xx 4 xx 4 xx 4`
= `(256pi)/3cm^3`
Number of balls = `(( 256pi)/3)/((4pi)/3)`
= `(256pi)/3 xx 3/(4pi)`
= 64
APPEARS IN
संबंधित प्रश्न
A right circular cylinder just encloses a sphere of radius r (see figure). Find
- surface area of the sphere,
- curved surface area of the cylinder,
- ratio of the areas obtained in (i) and (ii).
Find the surface area of a sphere of diameter 21 cm.
Total volume of three identical cones is the same as that of a bigger cone whose height is 9 cm and diameter 40 cm. Find the radius of the base of each smaller cone, if height of each is 108 cm.
A hemi-spherical bowl has negligible thickness and the length of its circumference is 198 cm. Find the capacity of the bowl.
Spherical marbles of diameter 1.4 cm are dropped into beaker containing some water and are fully submerged. The diameter of the beaker is 7 cm. Find how many marbles have been dropped in it if the water rises by 5.6 cm.
A largest sphere is to be carved out of a right circular cylinder of radius 7 cm and height 14 cm. Find the volume of the sphere.
The cross-section of a tunnel is a square of side 7 m surmounted by a semi-circle as shown in the adjoining figure. The tunnel is 80 m long.
Calculate:
- its volume,
- the surface area of the tunnel (excluding the floor) and
- its floor area.
If the ratio of volumes of two spheres is 1 : 8, then the ratio of their surface areas is
Find the radius of the sphere whose surface area is equal to its volume .
Find the volume and surface area of a sphere of diameter 21 cm.
