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प्रश्न
Choose the correct option.
Which of the following is an example of the first law of thermodynamics?
विकल्प
The specific heat of an object explains how easily it changes temperatures.
While melting, an ice cube remains at the same temperature.
When a refrigerator is unplugged, everything inside of it returns to room temperature after some time.
After falling down the hill, a ball's kinetic energy plus heat energy equals the initial potential energy.
उत्तर
After falling down the hill, a ball's kinetic energy plus heat energy equals the initial potential energy.
Explanation:
There are three laws of thermodynamics. These laws explain the relationship between quantities such as heat, temperature, entropy, and work. The first law of thermodynamics defines that for the change in the internal energy, which becomes equal to the heat that adds to the system minus the work which is done by the system.
The expression obtained is,
ΔU = Q – W
Here, ΔU is the change in internal energy.
Q is the heat added to the system.
W is the work done by the system.
The second law of thermodynamics defines that the total entropy in an isolated system will never decrease, and this is a constant only if all the process is reversible.
The third law of thermodynamics defines that the entropy in a system at the absolute zero temperature is a constant. Because the system here at zero temperature gets exists in the ground state.
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संबंधित प्रश्न
Write the mathematical expression of the First Law of Thermodynamics for Isothermal Process
Write the mathematical expression of the First Law of Thermodynamics for the Isobaric process.
A system can be taken from the initial state p1, V1 to the final state p2, V2 by two different methods. Let ∆Q and ∆W represent the heat given to the system and the work done by the system. Which of the following must be the same in both the methods?
The internal energy of an ideal gas decreases by the same amount as the work done by the system.
(a) The process must be adiabatic.
b) The process must be isothermal.
(c) The process must be isobaric.
(d) The temperature must decrease.
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When a system is taken through the process abc shown in figure, 80 J of heat is absorbed by the system and 30 J of work is done by it. If the system does 10 J of work during the process adc, how much heat flows into it during the process?
50 cal of heat should be supplied to take a system from the state A to the state B through the path ACB as shown in figure. Find the quantity of heat to be suppled to take it from A to B via ADB.
The internal energy of a gas is given by U = 1.5 pV. It expands from 100 cm3 to 200 cm3against a constant pressure of 1.0 × 105 Pa. Calculate the heat absorbed by the gas in the process.
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When heat energy of 2000 joules is supplied to a gas at constant pressure 2.1 x 105 N/m2, there is an increase in its volume equal to 2.5 x 10-3 m3. The increase in internal energy of the gas in joules is ____________.
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Consider two containers A and B containing identical gases at the same pressure, volume and temperature. The gas in container A is compressed to half of its original volume isothermally while the gas in container B is compressed to half of its original value adiabatically. The ratio of final pressure of gas in B to that of gas in A is ______.
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Is it possible to increase the temperature of a gas without adding heat to it? Explain.
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A to B : volume constant
B to C : adiabatic
C to D : volume constant
D to A : adiabatic
VC = VD = 2VA = 2VB
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- What is the work done by the engine in one cycle? Write your answer in term of PA, PB, VA.
- What is the efficiency of the engine?
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Using the first law of thermodynamics, show that for an ideal gas, the difference between the molar specific heat capacities at constant pressure and at constant volume is equal to the molar gas constant R.
In an adiabatic expansion of 2 moles of a gas, the initial pressure was 1.013 × 105 Pa, the initial volume was 22.4 L, the final pressure was 3.191 × 104 Pa and the final volume was 44.8 L. Find the work done by the gas on its surroundings. Taken `γ = 5/3`.
What is Isobaric process?
Show that the heat absorbed at constant pressure is equal to the change in enthalpy of the system.
Obtain an expression for the workdone by a gas in an isothermal process.
