The hollow metal pipe is 63 cm long. The inner diameter of cross-section is 4 cm and the outer diameter is 4.8 cm. Find the total surface area of the pipe.

Sub Grade: 9

see full answer

Start JEE / NEET / Foundation preparation at rupees 99/day !!

21% of IItians & 23% of AIIMS delhi doctors are from Sri Chaitanya institute !!

An Intiative by Sri Chaitanya

1734.46 cm2

1834.43 cm2

1834.46 cm2

1537.48 cm2

answer is A.

(Unlock A.I Detailed Solution for FREE)

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Detailed Solution

Length = 63 cm , or we can say height =63 cm
Inner diameter= 4cm   , outer diameter = 4 .8 cm
Inner diameter of crossetion = inner diameter /2 = 4/2 = 2
Let it be r = 2 cm
Similarly outer radius be R
R = 4.8 / 2 = 2.4 cm
Total sufacaae of hollow pipe = curved surface area of inner cylindrical part + curved surface area of outer cylindrical part + area of the two circular ends
Area of circular ends = area of outer circle - area of inner circle
π R2- π r2
π ( R2- r2)
Substituting volume of R and r
π ( 2.4 )2 - (2)2 )
π (1. 76 )cm2    Area of 2 circular lease= 2X 1.76 π cm2 = 3.52 π cm2
Curved surface area = 2 π radius X radius X height
Curved surface area of outer circle = 2π Rh = 2 x π X2.4 x63 = 302.45 π cm2 Curved surface area of inner circle = 2π Rh = 2 x π x 2 x 63 = 252 π cm2   On substituting (1)(2) and (3)
Total surface area= 252 π+ 302.45 π+ 3.52 π
= 557.92 π
=557.92 x 3.14 = 1734.46 cm2

Watch 3-min video & get full concept clarity