Advertisements
Advertisements
प्रश्न
A gas is initially at a pressure of 100 kPa and its volume is 2.0 m3. Its pressure is kept constant and the volume is changed from 2.0 m3 to 2.5 m3. Its Volume is now kept constant and the pressure is increased from 100 kPa to 200 kPa. The gas is brought back to its initial state, the pressure varying linearly with its volume. (a) Whether the heat is supplied to or extracted from the gas in the complete cycle? (b) How much heat was supplied or extracted?
Advertisements
उत्तर
(a) Given:-
P1 = 100 kPa,
V1 = 2 m3
V2 = 2.5 m3
∆V = 0.5 m3
Work done, W = P∆V
\[W = 100 \times {10}^3 \times 0 . 5\]
\[W = 5 \times {10}^4 J\]
WAB = Area under line AB = 5 × 104 J
If volume is kept constant for line BC, then ∆V = 0.
WBC = P∆V = 0
Work done while going from point B to C = 0
When the system comes back to the initial point A from C, work done is equal to area under line AC.
WCA = Area of triangle ABC + Area of rectangle under line AB
Total work done, W = Area enclosed by the ABCA
W = WAC - WAB
From the graph, we see that the area under AC is greater than the area under AB. We also see that heat is extracted from the system as change in the internal energy is zero.
(b) Amount of heat extracted = Area enclosed under ABCA
\[= \frac{1}{2} \times 0 . 5 \times 100 \times {10}^3 = 25000 J\]
APPEARS IN
संबंधित प्रश्न
When we rub our hands they become warm. Have we supplied heat to the hands?
Consider the process on a system shown in figure. During the process, the work done by the system ______________ .
An ideal gas goes from the state i to the state f as shown in figure. The work done by the gas during the process ______________ .
Consider two processes on a system as shown in figure.
The volumes in the initial states are the same in the two processes and the volumes in the final states are also the same. Let ∆W1 and ∆W2 be the work done by the system in the processes A and B respectively.
The pressure p and volume V of an ideal gas both increase in a process.
(a) Such a process is not possible.
(b) The work done by the system is positive.
(c) The temperature of the system must increase.
(d) Heat supplied to the gas is equal to the change in internal energy.
A gas is taken along the path AB as shown in figure. If 70 cal of heat is extracted from the gas in the process, calculate the change in the internal energy of the system.
A mixture of fuel and oxygen is burned in a constant-volume chamber surrounded by a water bath. It was noticed that the temperature of water is increased during the process. Treating the mixture of fuel and oxygen as the system,
- Has heat been transferred?
- Has work been done?
- What is the sign of ∆U?
Which of the following system freely allows the exchange of energy and matter with its environment?
When does a system lose energy to its surroundings and its internal energy decreases?
8 m3 of a gas is heated at the pressure 105 N/m2 until its volume increases by 10%. Then, the external work done by the gas is ____________.
Two samples A and B, of a gas at the same initial temperature and pressure are compressed from volume V to V/2; A isothermally and B adiabatically. The final pressure of A will be ______.
Which of the following represents isothermal process?
Two cylinders A and B of equal capacity are connected to each other via a stopcock. A contains a gas at standard temperature and pressure. B is completely evacuated. The entire system is thermally insulated. The stopcock is suddenly opened. Answer the following:
What is the change in internal energy of the gas?
In insulated systems, the amount of external work done by the gas is proportional to:
In thermodynamics, heat and work are ______.
A gas is compressed at a constant pressure of 50 N/m2 from a volume of 10 m3 to a volume of 4 m3. Energy of 100 J is then added to the gas by heating. Its internal energy is ______.
The internal energy of one mole of argon is ______.
A system releases 125 kJ of heat while 104 kJ work is done on the system. Calculate the change in internal energy.
