49.Spheres A and B have their radil 40 cm and 10 cm respectively. The ratio of the surface area of A to the surface area of B is
A. 1 : 4 B. 1 : 16
C. 4 : 1 D. 16 : 1
Answer:
Let the radil of A and B be r and R respectively.
Required ratio = 4Πr2/ 4ΠR2
‹=› r2 / R2
‹=› (r/R)2
‹=›(40/10)2
‹=› 16 : 1.
