00:01
Hello students, here the condition for quasi -static process is given.
00:06
First we need to draw p -v diagram that is pressure along y -axis, volume along x -axis.
00:19
In the question given that initially the gas is at 4 atmospheric pressure and at this condition volume v1 is 2 liter.
00:34
Then the gas is expanded and it comes to 3 atmospheric pressure.
00:46
At that time the volume is v2 which is 4 liter.
00:54
So this shows p -v diagram for the given process.
00:59
Now we need to calculate work done.
01:04
Work done is given by area under the curve.
01:09
So we know that work done is nothing but pressure into volume.
01:13
For pressure we can consider 4 atmospheric pressure.
01:18
At that time volume is 2 liter.
01:25
Now for atmospheric pressure substitute 1 .013 into 10 power 5 which is in pascal.
01:35
Given that atmospheric pressure is 101 .325 joules but we are converting it to pascal by first converting to kilo joule that is 101325 and then kilo is kept at 10 power 5.
01:55
Now 2 liter is converted to meter cube which is nothing but 2 into 10 power minus 3.
02:01
From this calculation we obtain work done is equal to 904 joules.
02:09
Here we can observe work is done at this portion.
02:21
Next we need to calculate change in internal energy which is given by u2 minus u1.
02:32
Substitute for u2 990 joules minus u1 560 joules.
02:38
From this we get 430 joules...