A soap bubble, having radius of 1 mm , is blown from a detergent solution having a surface tension of 2.5 × 10^-2 N/m . The pressure inside the bubble - Physics MCQ NEET 2019 2026 | ExamTest.live

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A soap bubble, having radius of 1 mm, is blown from a detergent solution having a surface tension of 2.5 \times 1 0^{- 2} N/m . The pressure inside the bubble equals at a point Z_{0} below the free surface of water in a container. Taking g = 10 m/s^{2}, density of water = 1 0^{3} kg/m^{3}, the value of Z_{0} is:

Solution & Step-by-step Explanation

Excess pressure inside a soap bubble is Δ P = \frac{4 T}{R} .Pressure inside the bubble P_{in} = P_{a t m} + \frac{4 T}{R} .Pressure at depth Z_{0} in water is P_{d e pt h} = P_{a t m} + ρ g Z_{0} .Setting them equal: \frac{4 T}{R} = ρ g Z_{0} Z_{0} = \frac{4 T}{ρ g R} = \frac{4 \times 2.5 \times 1 0 ^{- 2}}{1 0 ^{3} \times 10 \times 1 0 ^{- 3}} = \frac{10 \times 1 0 ^{- 2}}{10} = 1 0^{- 2} m Z_{0} = 1 cm

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A soap bubble, having radius of 1 mm, is blown from a detergent solution having a surface tension of 2.5 \times 1 0^{- 2} N/m . The pressure inside the bubble equals at a point Z_{0} below the free surface of water in a container. Taking g = 10 m/s^{2}, density of water = 1 0^{3} kg/m^{3}, the value of Z_{0} is:

100 cm

10 cm

1 cm

0.5 cm

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