Practice question

Excess pressure in a bubble: ΔP = 4Sr. ΔP = 20Pa, r = 7×10−3m. S = ΔP⋅r4 = 20×7×10−34 = 0.035N/m. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 0.035 N/m. This satisfies dimensional consistency and physical conditions given, so option D is scientifically correct.