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2) In the figures below, there is a blue sphere with a homogenous charge distribution. With gray color, various imagined surfaces have been shownH (cube, sphere x 2, open semi-sphere or a kind of "bowl"). a) Write Gauss' law and tell, which of these surfaces can be used in applying Gauss' law, i.e., which of the surfaces fulfill the conditions of so called Gauss' surface? b) Which of these surfaces is useful in calculating electric field of the charged sphere using Gauss' law? c) Using Gauss' law and suitably chosen Gauss' surface, show that the electric field inside a hollow uniformly charged sphere is zero