good thermo question

A straight glass tube has sealed lower end and upper end open to atmosphere.The lower half is filled with n moles of diatomic gas .The length of the tube is 1.52 m

How much heat should be provided to the gas such that all the mercury is pushed out of the tube,given that

(Atm Pressure in SI units) * (Are of cross-section of tube ) * 0.76m = 16J

The answer given is 27 joules,how do you solve this?i was gettin 24J from a linear P-V plot

10 Answers

1
gsns gannavarapu ·

mercury is present in upper half completely??or onli a particular lenght??

1
skygirl ·

hmm ... point...

1
Vivek ·

upper half completely - 76 cm Hg,76 cm gas

1
Vivek ·

not open test,it came in one of the fiitjee tests before the open test

3
iitimcomin ·

this is how i solved on paper too lazy to solve again hope u understand!!!!

im in 11 and this came in mah open test!!!!!!!!

3
iitimcomin ·

sorry itz all mixed up becuz i just rote it to solve it not to xplain to anyone!!!!!!
anyway wat ive done is that ive found pressure for a given vol. v and done PdV !!!!!!!!!!!!

1
Vivek ·

i got 24 too,i did something similar,but the answer given by fiitjee is "27",or maybe its just a standard fiitjee goofup

3
iitimcomin ·

no yaar it came in open test and even in the soln. key it was given as 24J so im damn sure!!!!!!!!!

3
iitimcomin ·

it came in 11std open test ... may be ur in 12!!!!!!!!!!!!

1
Vivek ·

hmmm,maybe fiitjee's answer in that key was wrong

Your Answer

Close [X]