Question

14. If the rallius of cylinder is halved and height is doubled, then the curved surface area will be
(a) increase by 1
(b) the same
(c) double
(d) triple​

Answer 1

Given :-

If the radius of cylinder is halved and height is doubled, then the curved surface area will be

Solution :-

→ As we know that ,

CSA of cylinder =  2πrh  

→ Now, if  :

$\sf r = \dfrac{r}{2} \\\\\\and \\\\h = 2h$

→  New CSA :

$\sf 2\pi (\dfrac{r}{2}) \times h \times 2 \\\\\\= 2\pi rh$

∴  It will remain same and option b is answer !

Answer 2

$\sf{Answer}$

step by step explanation:-

In cylinder CSA of cylinder is

CSA of cylinder is 2πrh

But ATQ

Radius of cylinder is halved

Hence new radius = r/2

Height of cylinder is doubled

Hence new height is 2h

New CSA of cylinder is

CSA = 2πrh

NEW CSA = 2π × $\frac{r}{2}$ × 2h

New CSA = 2πrh

Hence remains same (b)

Hope my answer helps to u

Thank u :)