Why does a bubble collapse when the external pressure exceeds its internal pressure?
The excess pressure inside a bubble (4S/r) balances the external pressure. If external pressure exceeds this, the net inward force overcomes surface tension’s resistance, causing the bubble to collapse. As per NCERT, applying relevant law/formula with correct units and sign convention leads to Net inward force dominates. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.
Ref: NCBI Bookshelf, Ideal Gas Law: P1V1/T1 = P2V2/T2.
