If the radii of two spheres are in the ratio 1 : 4, then their surface areas are in the ratio :

A. 1 : 2

B. 1 : 4

C. 1 : 8

D. 1 : 16

Answer: Option D

Solution(By Examveda Team)

Let the radii of the two spheres be r and 4r respectively.
Then,
Required ratio :
$$\eqalign{ & = \frac{{4\pi {r^2}}}{{4\pi {{\left( {4r} \right)}^2}}} \cr & = \frac{{{r^2}}}{{16{r^2}}} \cr & = \frac{1}{{16}} \cr & = 1:16 \cr} $$