A soap bubble of radius 3 cm is formed inside the another soap bubble of radius 6 cm. The radius of an equivalent soap bubble which has the same excess pressure as inside the smaller bubble with respect to the atmospheric pressure is ................ cm.
Answer (integer)
2
Solution
Image<br><br>Excess pressure inside the smaller soap bubble<br><br>$\Delta P = {{4S} \over {{r_1}}} + {{4S} \over {{r_2}}}$ .... (i)<br><br>The excess pressure inside equivalent soap bubble<br><br>$\Delta P = {{4S} \over {{R_{eq}}}}$ ....... (ii)<br><br>From (i) & (ii)<br><br>${{4S} \over {{R_{eq}}}} = {{4S} \over {{r_1}}} + {{4S} \over {{r_2}}}$<br><br>${1 \over {{R_{eq}}}} = {1 \over {{r_1}}} + {1 \over {{r_2}}}$<br><br>$= {1 \over 6} + {1 \over 3}$<br><br>R<sub>eq</sub> = 2 cm
About this question
Subject: Physics · Chapter: Properties of Solids and Liquids · Topic: Elasticity
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