Answer:
Option A
Explanation:
Surface area A of a cube of side x is given by A=6x2.
on differentiating w.r.t x , we get $\frac{dA}{dx}=12x$
Let the change in x be $\triangle x$ = m% of x = $\frac{mx}{100}$
Change in surface area,
$\triangle A= \left(\frac{dA}{dx}\right)\triangle x=(12x)\triangle x$
= $12 x \left(\frac{mx}{100}\right)=\frac{12x^{2}m}{100}$
The approximate change in surface area = $\frac{2m}{100}\times6x^{2}$
=2m% of original surface area
