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Thermal Physics

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23 Jan 2008 10:17:13 IST

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gas laws questions

None

1) a column of air 40cm long in a glass tube with a cross sectional area 0.5 cm square and arrranged vertically with a sealed end upward is isolated by a column of Hg 8cm long. the temperature is 27 degree celsius.how will the length of the air column change, if the tube is inclined at 60 degree celsius from the vertical and the temperature is simultaneously raised by 30 degree celsius? assume the atmospheric pressure to be 76cm of Hg and neglect expansion of glass and mercury?

ANS: the length of the air column is increases by 1.5cm

2)an air bubble doubles in radius on rising from bottom of lake to its surface. if the atmpspheric pressure is equyal to that due to column of 10m water, then the depth of the lake is

a) 80 m b)70m c)40m d)10m

ANS:b

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Himanshu

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Joined: 19 Feb 2007

Posts: 3834

23 Jan 2008 10:37:21 IST

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ans2) the radius gets doubled...

so , by this relation

v = (4/3)(pi) r³ , volume becomes 8 times....

it means pressure at the bottom of lake is 8 times the pressure at the surface

so pressure due to depth of the lake = 80 - 10 = 70

neha

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Joined: 13 Aug 2007

Posts: 25

23 Jan 2008 10:46:29 IST

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any1 pls solve d first question...

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