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
Find the total surface area of a hemisphere of radius 10 cm. [Use π = 3.14]
A model of a ship is made to a scale 1: 300
1) The length of the model of the ship is 2 m. Calculate the lengths of the ship.
2) The area of the deck ship is 180,000 m2. Calculate the area of the deck of the model.
3) The volume of the model in 6.5 m3. Calculate the volume of the ship.
Find the surface area of a sphere of diameter 14 cm.
Find the surface area of a sphere of diameter 21 cm.
Find the surface area of a sphere of diameter 3.5 cm.
The dome of a building is in the form of a hemisphere. Its radius is 63 dm. Find the cost of painting it at the rate of Rs. 2 per sq. m.
How many balls each of radius 1 cm can be made by melting a bigger ball whose diameter is 8 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 total surface area of a hemisphere of radius r is
The ratio of the total surface area of a sphere and a hemisphere of same radius is
If the surface area of a sphere is 144π m2, then its volume (in m3) is
A hemispherical and a conical hole is scooped out of a.solid wooden cylinder. Find the volume of the remaining solid where the measurements are as follows:
The height of the solid cylinder is 7 cm, radius of each of hemisphere, cone and cylinder is 3 cm. Height of cone is 3 cm.
Give your answer correct to the nearest whole number.Taken`pi = 22/7`.
Find the surface area and volume of sphere of the following radius. (π = 3.14 )
9 cm
Find the surface area of a sphere, if its volume is 38808 cubic cm. `(π = 22/7)`
A certain number of metallic cones, each of radius 2 cm and height 3 cm are melted and recast into a solid sphere of radius 6 cm. Find the number of cones used.
A vessel is in he form of an inverted cone. Its height is 11 cm., and the radius of its top which is open is 2.5 cm. It is filled with water up to the rim. When lead shots, each of which is a sphere of radius 0.25 cm., are dropped 2 into the vessel, `2/5`th of the water flows out. Find the number of lead shots dropped into the vessel.
The internal and external diameters of a hollow hemispherical vessel are 20 cm and 28 cm respectively. Find the cost to paint the vessel all over at ₹ 0.14 per cm2
A solid sphere is cut into two identical hemispheres.
Statement 1: The total volume of two hemispheres is equal to the volume of the original sphere.
Statement 2: The total surface area of two hemispheres together is equal to the surface area of the original sphere.
Which of the following is valid?
