First slide

Surface tension

Question

The radius of a soap bubble is increased from $\frac{1}{\sqrt{π}}$ cm to $\frac{2}{\sqrt{π}}$ cm. If the surface tension of water is 30 dynes per cm, then the work done will be

Moderate

A

180 ergs
B

360 ergs
C

720 ergs
D

960 ergs

Solution

W = 8 $πT (r_{2}^{2} - r_{1}^{2}) = 8 πT [{(\frac{2}{\sqrt{π}})}^{2} - {(\frac{1}{\sqrt{π}})}^{2}]$
$∴ W = 8 \times π \times 30 \times \frac{3}{π} = 720 ergs$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App