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प्रश्न
Water is flowing through a long horizontal tube. Let PA and PB be the pressures at two points A and B of the tube.
विकल्प
PA must be equal to PB.
PA must be greater than PB.
PA must be smaller than PB.
PA = PB only if the cross-sectional area at A and B are equal.
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उत्तर
PA = PB because the cross-sectional areas at A and B are equal.
According to Bernoulli's theorem, pressures at points A and B of the horizontal tube will be equal if water has the same velocity at these points.
Also, according to the equation of continuity, velocity at points A and B will be equal only if the cross-sectional areas at A and B are equal.
So, PA = PB only if the cross-sectional areas at A and B are equal.
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