Question

The boiler is essentially a closed vessel inside which water is stored. Fuel
(generally coal) is burnt in a furnace and hot gasses are produced. These hot gasses come in contact with water vessel where the heat of these hot gases transfer to the water and consequently steam is produced in the boiler. Then this steam is piped to the turbine of thermal power plant. There are many different types of boiler utilized for different purposes like running a production unit, sanitizing some area, sterilizing equipment, to warm up the surroundings etc.
Rajesh has been given the task of designing a boiler for NTPC. Boiler consist of a cylindrical part in middle and two hemispherical part its both end. The cross section of boiler is given below. Length of cylindrical part is the 3 times of radius of hemispherical part.
On the basis of the above information, answer any four of the following questions:
(a) Which of the following is correct expression for the surface area of cylindrical part of Boiler?
(i) 2r2 (ii) 6r2 (iii) 4r2 (iv) 8r2

Answer 1

Answer:

a )ii b)iii c)i

Step-by-step explanation:

volume of cylinder= 2πrh

since h=3r

volume of cylinder= 2πr(3r)

                            =6πr²

b)

volume of boiler= 2×volume of hemisphere+volume of cylinder

                         =2×2/3πr³+πr²h

                       =4/3πr³+πr²3r

                      =13/3πr³

c)

area of boiler= 2×csa of hemisphere+csa of cylinder

                    =4πr²+6πr²

                    =10πr²

therefore ratio=13/3πr³/10πr²

                       =13r/30