Question:
A wire forming a loop is dipped into soap solution and taken out so that a film of soap solution is formed. A loop of $6.28 \mathrm{~cm}$ long thread is gently put on the film and the film is pricked with a needle inside the loop. The thread loop takes the shape of a circle. Find the tension in the thread. Surface tension of soap solution $=0.030 \mathrm{~N} / \mathrm{m}$.
Solution:
