If S1 and S2 be the whole surface of a sphere and the curved surface of the circumscribed cylinder, then S1 is equal to
a)S2, b)2S2 c)(1/2)S2 d)(2/3)S2

• ANS: A
  
  Explanation:
  Let the radius of the sphere be r.
  The radius of the circumscribing cylinder = r
  H = height of the cylinder = Diameter of the sphere = 2r
  Whole surface of the sphere = 4r^2 ___(1)
  Curved surface of the cylinder = (2r)H = (2r)2r = 4r^2 ___(2)
  From (1) and (2), Whole surface of a sphere = Curved surface of the circumscribed cylinder
  
  = 4r2
  
  
  
• 13 years agoHelpfull: Yes(5) No(1)