The work done in blowing a soap bubble of rad | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(C) The work done in blowing a soap bubble of radius $r$ is given by $W = 2 	imes (4 \pi r^2) 	imes T = 8 \pi r^2 T$,where $T$ is the surface tensio

Vedclass · Accepted Answer

$W_2 < 4 W_1$

Vedclass · Answer

(C) The work done in blowing a soap bubble of radius $r$ is given by $W = 2 	imes (4 \pi r^2) 	imes T = 8 \pi r^2 T$,where $T$ is the surface tension of the soap solution.For the first bubble of radius $R$ at room temperature with surface tension $T_1$,the work done is $W_1 = 8 \pi R^2 T_1$.For the second bubble of radius $2R$ at a higher temperature with surface tension $T_2$,the work done is $W_2 = 8 \pi (2R)^2 T_2 = 32 \pi R^2 T_2$.Comparing the two,we have $\frac{W_2}{W_1} = \frac{32 \pi R^2 T_2}{8 \pi R^2 T_1} = 4 \left( \frac{T_2}{T_1} ight)$.Since the soap solution is heated,the surface tension decreases,meaning $T_2 Therefore,$W_2 < 4 W_1$.

The work done in blowing a soap bubble of radius $R$ is $W_1$ at room temperature. Now the soap solution is heated. From the heated solution another soap bubble of radius $2R$ is blown and the work done is $W_2$. Then:

Similar Questions

$A$ soap bubble of radius $r$ is blown up to form a bubble of radius $2r$ under isothermal conditions. If $T$ is the surface tension of the soap solution, the energy spent in the blowing is: (in $\pi T r^2$)

Surface tension of a soap solution is $1.9 \times 10^{-2} \text{ N/m}$. The work done in blowing a soap bubble of $2.0 \text{ cm}$ diameter will be:

Energy required to form a soap bubble of diameter $20 \, cm$ will be (Surface tension for soap solution is $30 \, dynes/cm$)

The energy needed for breaking a liquid drop of radius '$R$' into '$n$' droplets each of radius '$r$' is [$T$ = surface tension of the liquid]

Energy needed in breaking a liquid drop of radius $R$ into $n$ smaller drops,each of radius $r$,is [where $T$ is the surface tension of the liquid].

Vedclass Test Series

Exam Paper Generator

Online Exam Module