P-V Diagram Question - Can Q1<Q2<Q3?

AI Thread Summary
In the discussion about the P-V diagram and heat absorbed by an ideal gas transitioning between states A and B, it is argued that Q1 is less than Q2, which is less than Q3, based on temperature differences. The reasoning states that lower temperatures correspond to lower heat absorption, leading to the conclusion that Q1<Q2<Q3. Additionally, it is noted that the work done by the gas, represented by the area under the P-V curve, also influences the amount of heat absorbed, with greater work correlating to greater heat. The relationship between heat, internal energy, and work is highlighted, emphasizing that the path with the most work done will have the highest heat addition. Overall, the discussion confirms that the heat absorbed varies with the path taken, influenced by both temperature and work done.
Amith2006
Messages
416
Reaction score
2
Sir,
An ideal gas of mass m in a state A goes to another state B via 3 different processes as shown in the figure. If Q1, Q2 and Q3 denote the heat absorbed by the gas along the 3 paths, can we say that Q1<Q2<Q3?
I solved it in the following way:
From the figure it is clear that T1<T2<T3. Now, smaller the temperature smaller will be the heat absorbed by the gas. Therefore, Q1<Q2<Q3. Is my argument right?
 
Physics news on Phys.org
Amith2006 said:
Sir,
An ideal gas of mass m in a state A goes to another state B via 3 different processes as shown in the figure. If Q1, Q2 and Q3 denote the heat absorbed by the gas along the 3 paths, can we say that Q1<Q2<Q3?
I solved it in the following way:
From the figure it is clear that T1<T2<T3. Now, smaller the temperature smaller will be the heat absorbed by the gas. Therefore, Q1<Q2<Q3. Is my argument right?
I am herewith attaching the P-V diagram.
 

Attachments

  • Diagram5.JPG
    Diagram5.JPG
    4.7 KB · Views: 539
Amith2006 said:
Sir,
An ideal gas of mass m in a state A goes to another state B via 3
different processes as shown in the figure. If Q1, Q2 and Q3 denote the
heat absorbed by the gas along the 3 paths, can we say that Q1<Q2<Q3?
I solved it in the following way:
From the figure it is clear that T1<T2<T3. Now, smaller the temperature
smaller will be the heat absorbed by the gas. Therefore, Q1<Q2<Q3. Is my
argument right?
You can do it a couple of different ways. You can
see that if PV is greater for all points on on path 3 than on paths 1
and 2, the temperature must be greater, ie. more heat is present. But
you can also do it by looking at the work done by the gas.

Since: dQ = dU + dW where dW is the work done by the gas, and since dU
is the same for all, the greater heat occurs on the path where the
greatest amount of work is done by the gas.

I can't see your diagram, but assuming it is a PV diagram, the area
under the graph will give you the work done. The path with more area
under it has the greater heat added.

AM
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top