Gravitation

As the two masses are dropped,u = 0, a = g (which does not depend upon mass)
From s = ut + $\frac{1}{2}$$at2$
$h$₁=0+$\frac{1}{2}$$gt2$₁ and $h$₂=0+$\frac{1}{2}$$gt2$₂
∴$\frac{\mathrm{h₁}}{\mathrm{h₂}}$=$\left(\frac{\mathrm{t₁}}{\mathrm{t₂}}\right)$$2$ or $\frac{\mathrm{t₁}}{\mathrm{t₂}}$=$\sqrt{\frac{\mathrm{h₁}}{\mathrm{h₂}}}$
This ratio of time shall remain the same if
(i) one of the objects is hollow and the other one is solid - as the ratio is independent of masses.
(ii) both the objects are hollow, as acc. due is gravity (g) does not depend upon mass and also whether the body is hollow/solid.
As size remains the same in each case,there is no effect of resistance due to air in the two cases.