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Physics · PYQ NEET UG 2019(1)
हिन्दीA soap bubble, having radius of \( 1\text{ mm} \), is blown from a detergent solution having a surface tension of \( 2.5 \times 10^{-2}\text{ N/m} \). The pressure inside the bubble equals at a point \( Z_0 \) below the free surface of water in a container. Taking \( g = 10\text{ m/s}^2 \), density of water \( = 10^3\text{ kg/m}^3 \), the value of \( Z_0 \) is:
Correct answer · Option 1
1 cm
Explanation
Excess pressure inside soap bubble is \( P = \frac{4T}{R} = \rho g Z_0 \). Substituting values gives \( Z_0 = \frac{4 \times 2.5 \times 10^{-2}}{10^{-3} \times 10 \times 10^{-3}} = 0.01\text{ m} = 1\text{ cm} \).
