Question

can anyone write the final exp for work done in a carnot cycle? after applying sign convention..

Answer 1

@ganeshie8 @ParthKohli

Answer 2

Net work done =?

Answer 3

Combination of two adiabatic and two isothermal processes.

Answer 4

@Rushwr.. i know how to calculate work done for each stroke and then add up... but i am confused in the sign..part..that can change the final value itself... thats why i am asking..

Answer 5

@samigupta8

Answer 6

U need derivatiion of that?

Answer 7

If u r desiring the same then i must say do as suggested by @parthkohli

Answer 8

I know how to derive it but i am confused with the sign convention as i have mentioned above @samigupta8 did you see?

Answer 9

i also know that
work done by gas = +ve
work done on gas = -ve

Answer 10

That again means the same u need derivation of the whole process .
If you r not getting the proper sign convention then that means u need to recheck that ...
Or better you post your work i will see fault in it

Answer 11

but i think in my book they have applied it twice..

Answer 12

Where they have applied twice?
I checked it there is no such thing as that...
And if u still have doubt pls check for once carefully bcoz all that's mentioned is exactly perfect...no fault in it

Answer 13

in the book .. they have used sign convention to calculate W3 and W4 but in the end they have again written W1+W2-W3-W4..Why so?

Answer 14

@samigupta8 i checked again.. ok.. pls Explain how we got W3 using the formula for adiabatic process..in the formula we have (Ti - Tf) i->initial f->final .. but in the book they have given negative of this..

Answer 15

They have given it since we need to calculate work done for the complete cycle ..
If u draw the area under each part of the cycle and then add isothermal and adiabatic expansion processes and subtract the two compression processes you will get the area under curve which is carnot cycle

Answer 16

@samigupta8 i have a doubt in W4.. that is adiabatic compression.. if you see in the book they have given (Tf-Ti) but actually it is (Ti-Tf)...Why so?

Answer 17

It's a compression process and we need to consider the sign for that...
Compression means work is done on the gas which is -ve so we have to consider that sign

Answer 18

ok then why they have again used -W4? why minus sign again while finding net work done.. this is what i meant by saying they have applied sign convention "twice".. @samigupta8

Answer 19

I gave the reason in my previous post...
Pls see that

Answer 20

hey you are not understanding my doubt...

Answer 21

i am asking why we are writing with a minus both while calculating the work done and while calculating the total work done..we are again writing.. W1+W2-W3-W4 ? why two negative signs??

Answer 22

I replied to that thing only in my first post for this question...
Back 23 hours ago...

Answer 23

Thanks @samigupta8 !

Answer 24

Np:)