A sphere of relative density σ and diameter D has concentric cavity of diameter d. The ratio of \(\rm \frac{D}{d}\), if it just floats on water in a tank is:
1
\(\rm \left(\frac{\sigma}{\sigma-1}\right)^\frac{1}{3}\)
2
\(\rm \left(\frac{\sigma+1}{\sigma-1}\right)^\frac{1}{3}\)
3
\(\rm \left(\frac{\sigma-1}{\sigma}\right)^\frac{1}{3}\)
4
\(\rm \left(\frac{\sigma-2}{\sigma+2}\right)^\frac{1}{3}\)
5
Question Not Attempted