Question

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Answer 1

When the glass tube was in mercury with half dipped Pressure on top of mecury should be equal to mercury pressure Therefore that pressure will be P(1) =13.6g(40)Now after taking tube out thumb is placed on the top so This should apply there also there now in this condition the pressure of mercury + P1= atmospheric pressure applying now on the other open end Therefore Atmospheric pressure=P1+13.6g(20) = 13.6g(40)+13.6g(20) =13.6g(60)Atmospheric pressure =60 cm of Hg column
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