Question

At which of the following temperatures, the value of surface tension of water is minimum?

• A. $4{}^{\circ }C$
• B. $25{}^{\circ }C$
• C. $50{}^{\circ }C$
• D. $75{}^{\circ }C$

Answer 1

Answer: (D)

The surface tension of water is $72$ dyne $/cm$ at $25^{\circ }C$. It would take a force of $72$ dyne to break a surface film of water $1cm$ long. The surface tension of water decreases significantly with temperature as shown in the graph below.

Out of the given four options $75^{\circ }C$ is the highest temperature, at which surface tension is lowest.