Let Terminal velocity =vt Upward viscous force = downward weight of sphere ⇒6πηrvt=(
4
3
πr3)(ρ−σ)g ⇒vt=
2r2(ρ−σ)g
9η
........(1) where, ρ= density of substance of a body σ= density of liquid Now let the terminal velocity of gold =vg and silver =vS. From equation (1), we can write