Advertisements
Advertisements
प्रश्न
The diameter of the moon is approximately one fourth of the diameter of the earth. Find the
ratio of their surface areas.
Advertisements
उत्तर
Let the diameter of the earth is d then, diameter of moon will be `d/4`
Radius of earth =`d/2`
Radius of moon = `2/4=d/8`
S.A of moon = `4πr(d/8)^2`
Surface area of earth = `4πr(d/2)^2`
Required ratio = `(4πr(d/8)^2)/(4πr(d/2)^2) = 4/64=1/16`
Thus, the required ratio of the surface areas is `1/16`.
APPEARS IN
संबंधित प्रश्न
A hemispherical bowl made of brass has inner diameter 10.5 cm. Find the cost of tin-plating it on the inside at the rate of ₹ 16 per 100 cm2.
`["Assume "pi=22/7]`
The diameter of the moon is approximately one-fourth of the diameter of the earth. Find the ratio of their surface area.
Find the surface area of a sphere of diameter 21 cm.
A hollow sphere of internal and external diameter 4 cm and 8 cm respectively is melted into a cone of base diameter 8 cm. Find the height of the cone.
A solid is in the form of a cone standing on a hemi-sphere with both their radii being equal to 8 cm and the height of cone is equal to its radius. Find, in terms of π, the volume of the solid.
The diameter of a sphere is 6 cm. It is melted and drawn into a wire of diameter 0.2 cm. Find the length of the wire.
The hollow sphere, in which the circus motor cyclist performs his stunts, has a diameter of 7 m. Find the area available to the motorcyclist for riding.
If a solid sphere of radius 10 cm is moulded into 8 spherical solid balls of equal radius, then the surface area of each ball (in sq.cm) is
If a sphere is inscribed in a cube, then the ratio of the volume of the sphere to the volume of the cube is
A sphere is placed inside a right circular cylinder so as to touch the top, base and lateral surface of the cylinder. If the radius of the sphere is r, then the volume of the cylinder is
The ratio between the volume of a sphere and volume of a circumscribing right circular cylinder is
A cone, a hemisphere and a cylinder stand on equal bases and have the same height. The ratio of their volumes is
A hemispherical bowl of internal radius 9 cm is full of liquid. This liquid is to be filled into conical shaped small containers each of diameter 3 cm and height 4 cm. How many containers are necessary to empty the bowl?
From a rectangular solid of metal 42 cm by 30 cm by 20 cm, a conical cavity of diameter 14 cm and depth 24 cm is drilled out. Find: the volume of remaining solid
The given figure shows the cross-section of a cone, a cylinder and a hemisphere all with the same diameter 10 cm and the other dimensions are as shown.
Calculate :
- the total surface area.
- the total volume of the solid and
- the density of the material if its total weight is 1.7 kg.
A sphere cut out from a side of 7 cm cubes. Find the volume of this sphere?
How many spherical bullets can be made out of a solid cube of lead whose edge measures 44 cm, each bullet being 4 cm in diameter?
The total surface area of a hemisphere is how many times the square of its radius
