Fluid Mechanics Viscosity Question 345

Question: The amount of work done in forming a soap film of size $ 10,cm\times 10,cm $ is (Surface tension $ T=3\times {{10}^{-2}},N/m) $ [MP PET 1994; MP PET 2000]

Options:

A) $ 6\times {{10}^{-4}},J $

B)$ 3\times {{10}^{-4}},J $

C) $ 6\times {{10}^{-3}},J $

D)$ 3\times {{10}^{-4}},J $

Show Answer

Answer:

Correct Answer: A

Solution:

$ E=T\times \Delta A=3\times {{10}^{-2}}\times 2(100\times {{10}^{-4}})=6\times {{10}^{-4}}J $