Advertisements
Advertisements
प्रश्न
Find the total surface area of an open pipe of length 50 cm, external diameter 20 cm and internal diameter 6 cm.
उत्तर
Length of an open pipe = 50 cm
External diameter = 20 cm `=>` External radius (R) = 10 cm
Internal diameter = 6 cm `=>` Internal radius (r) = 3 cm
Surface area of pipe open from both sides = 2πRh + 2πrh
= 2πh(R + r)
= `2 xx 22/7 xx 50 xx (10 + 3)`
= 4085.71 cm2
Area of upper and lower part = 2π(R2 – r2)
= `2 xx 22/7 xx (10^2 - 3^2)`
= `2 xx 22/7 xx (100 - 9)`
= `2 xx 22/7 xx 91`
= 572 cm2
Total surface area = 4085.714 + 572
= 4657.71 cm2
APPEARS IN
संबंधित प्रश्न
A cylindrical can, whose base is horizontal and of radius 3.5 cm, contains sufficient water so that when a sphere is placed in the can, the water just covers the sphere. Given that the sphere just fits into the can, calculate:
- the total surface area of the can in contact with water when the sphere is in it;
- the depth of water in the can before the sphere was put into the can.
How much iron is needed to make a rod of length 90 cm and diameter 1.4 cm?
The height of a circular cylinder is 20 cm and the radius of its base is 7 cm. Find : the total surface area.
If the radius of the base of a right circular cylinder is halved keeping the same height, then the ratio of the volume of the cylinder thus obtained to the volume of original cylinder is
The ratio of the volumes of a cylinder, a cone and a sphere, if each has the same diameter and same height is
A cone, a hemisphere and a cylinder stand on equal bases and have the same height. The ratio of their volumes is 1 : 2 : 3.
The volume of a cylinder whose radius r is equal to its height is ______.
Two cylinders of same volume have their radii in the ratio 1 : 6, then ratio of their heights is ______.
How many cubic metres of earth must be dug to construct a well 7 m deep and of diameter 2.8 m?
A hollow garden roller of 42 cm diameter and length 152 cm is made of cast iron 2 cm thick. Find the volume of iron used in the roller.
