What is the bubble's diameter just as it reaches the surface of the lake, where the water temperature is 20∘C? Assume that the air bubble is always in thermal equilibrium with the surrounding water.

Light from two different sources are incident upon the same side of a polarizing filter. light from one source is polarized with total intensity ip, while light from the other source is unpolarized with total intensity iu. as you rotate the polarizing filter through 360 degrees, the intensity of the transmitted light on the other side varies by a factor of 9. what is the relative intensity of the initial polarized source to the unpolarized source, or ip/iu?