Gautam visited a fair along with his classmates. There he found that a hawker was selling balloons filled with helium gas. His teacher told the students that the balloons will rise in the sky and then stop after some distance. Gautam questioned his teacher as to why the balloons would stop. He started arguing with his teacher that the balloons would rise indefinitely. His teacher got irritated with him. Just then,Gautam's friend Avdesh took him aside and explained to him that the teacher was correct. The explanation given by Avdesh satisfied Gautam.
$(a)$ Why will the balloon stop after rising to a certain height?
$(b)$ What values are shown by Avdesh and Gautam?

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(A) The mass of the balloon filled with helium is less than the mass of the air displaced by it. Hence,the upthrust acting on the balloon is more than its weight. As a result,the balloon experiences a net upthrust which makes it rise. As the balloon rises,it experiences less and less upthrust due to the fact that the density of air decreases with height. At a certain point,the weight of the balloon is completely balanced by the upthrust acting on it. Thereafter,the balloon stops rising.
$(b)$ Value shown by Avdesh: Respect for the teacher and knowledge of the subject.
Value shown by Gautam: Logical reasoning.

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