Radius of a large sphere is 28 m. If it is melted to form 8 equal small solid sphere, what is the sum of total surface areas of all the 8 small solid spheres?
Answer & explanation
Correct answer: option 3
Volume of large solid spheres = volume of 8 small spheres
\(\frac{4}{3}\)\(\pi \)R3 = 8 × \(\frac{4}{3}\)\(\pi \)r3
\(\frac{28×28×28}{2 × 2 × 2}\) = r3
r = 14
Total surface area of solid sphere = 4\(\pi \)r2
T.S.A. of all 8 spheres = 8 × 4 × \(\frac{22}{7}\) × 14 × 14 = 19712 cm2