If the height of a cylinder becomes 14 of the original height and the radius is doubled, then which of the following will be true ?
(a) Curved surface area of the cylinder will be doubled
(b) Curved surface area of the cylinder will remain unchanged
(c) Curved surface area of the cylinder will be halved
(d) Curved surface area will be 14 of the original curved surface
Let the new height and radius be h4 and 2r respectively, where r and h are orignal radius and original height respectively of the cylinder.
We know that, curved surface area of cylinder =2πrh
=12×2πrh [multiplying and dividing by 2]
=12 original curved surface area
Hence, the curved surface area of the cylinder will be halved.