Question 233: Properties of Matter

Question

A soap bubble is blown to a diameter of $$7 \mathrm{~cm}$$. $$36960 \mathrm{~erg}$$ of work is done in blowing it further. If surface tension of soap solution is 40 dyne/$$\mathrm{cm}$$ then the new radius is ________ cm Take $$(\pi=\frac{22}{7})$$.

Accepted Answer

$$\begin{aligned}
& \Delta W=8 \pi\left(R_2^2-R_1^2ight) T \
& 36960=8 	imes \frac{22}{7} 	imes 40\left(R_2^2-\frac{49}{4}ight) \
& R_2=7 \mathrm{~cm}
\end{aligned}$$

Properties of Matter

A soap bubble is blown to a diameter of $7 \mathrm{~cm}. 36960 \mathrm{~erg} of work is done in blowing it further. If surface tension of soap solution is 40 dyne/\mathrm{cm} then the new radius is ________ cm Take (\pi=\frac{22}{7})$.

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