Problem 6. (Surface tension in alveolus) An alveolus is essentially a spherical cavity (air surrounded by a fluid lining), and in fact alveolus is Latin for "little cavity". The pressure of the air inside an alveolus with a 200 m diameter is 1.40 103 Pa greater than the pressure inside its fluid-lined walls. What is the surface tension of the fluid lining the alveolus in units of ?