Question 870: Thermodynamics & KTG

Question

Let '$$\mathrm{W}_1$$' be the work done in blowing a soap bubble of radius '$$r$$' from soap solution at room temperature. The soap solution is now heated and second soap bubble of radius '$$2 r$$' is blown from the heated soap solution. If '$$W_2$$' is the work done in forming this bubble then

Accepted Answer

$$W_1=8 \pi r^2 T$$
where $$\mathrm{T}=$$ surface tension
$$\mathrm{W}_2=8 \pi(2 r)^2 \mathrm{~T}^{\prime}=32 \mathrm{r}^2 \mathrm{~T}^{\prime}$$
Since soap solution is heated, its surface tension decreases.
$$\begin{array}{ll}
	herefore \mathrm{T}^{\prime}\mathrm{W}_2
\end{array}$$

Answer

$$\mathrm{W}_2=2 \mathrm{~W}_1$$

Answer

$$\mathrm{W}_2=4 \mathrm{~W}_1$$

Answer

$$\mathrm{W}_2>4 \mathrm{~W}_1$$

Answer

$$\mathrm{W}_2<4 \mathrm{~W}_1$$

Thermodynamics & KTG

Let '$\mathrm{W}_1' be the work done in blowing a soap bubble of radius 'r' from soap solution at room temperature. The soap solution is now heated and second soap bubble of radius '2 r' is blown from the heated soap solution. If 'W_2$' is the work done in forming this bubble then

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