The buoyancy force acting on the gas bubble is (Assume R is the universal gas constant)
(1) ρℓnRT0(P0+ρℓgy)7/5(P0+ρℓgH)2/5
(2) (P0+ρℓgH)2/5[P0+ρℓg(H−y)]3/5ρℓnRT0
(3) ρℓnRT0(P0+ρℓgy)8/5(P0+ρℓgH)3/5
(4) (P0+ρℓgH)3/5[P0+ρℓg(H−y)]2/5ρℓnRT0