Advertisements
Advertisements
प्रश्न
Write the mathematical equation for the first law of thermodynamics for:
Isothermal process
Deduce the first law of thermodynamics for the isothermal process.
उत्तर
For isothermal process:
For a given temperature (T) and internal energy (U) of the remains constant.
∴ ΔT = 0
∴ ΔU = 0
First law of thermodynamic
ΔU = Q + W
0 = Q + W ...(∵ ΔU = 0)
∴ Q = – W
संबंधित प्रश्न
Write the mathematical expression of the First Law of Thermodynamics for the Isobaric process.
When we heat an object, it expands. Is work done by the object in this process? Is heat given to the object equal to the increase in its internal energy?
A thermally insulated, closed copper vessel contains water at 15°C. When the vessel is shaken vigorously for 15 minutes, the temperature rises to 17°C. The mass of the vessel is 100 g and that of the water is 200 g. The specific heat capacities of copper and water are 420 J kg−1 K−1 and 4200 J kg−1 K−1 respectively. Neglect any thermal expansion. (a) How much heat is transferred to the liquid-vessel system? (b) How much work has been done on this system? (c) How much is the increase in internal energy of the system?
The pressure of a gas changes linearly with volume from 10 kPa, 200 cc to 50 kPa, 50 cc. (a) Calculate the work done by the gas. (b) If no heat is supplied or extracted from the gas, what is the change in the internal energy of the gas?
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.
Answer the following in one or two sentences.
State the first law of thermodynamics.
For an Isothermal process
Define an isolated system.
ΔU is equal to ____________ work.
10 kg of four different gases (Cl2, CH4, O2, N2) expand isothermally and reversibly from 20 atm to 10 atm. The order of amount of work will be ____________.
A gas performs 0.320 kJ work on surrounding and absorbs 120 J of heat from the surrounding. Hence, change in internal energy is ______.
The process, in which no heat enters or leaves the system, is termed as ____________.
The isothermal bulk modulus of a perfect gas at pressure P is numerically equal to ____________.
An ideal gas undergoes cyclic process ABCDA as shown in given P-V diagram (figure). The amount of work done by the gas is ______.
Air pressure in a car tyre increases during driving. Explain.
A cycle followed by an engine (made of one mole of perfect gas in a cylinder with a piston) is shown in figure.
A to B : volume constant
B to C : adiabatic
C to D : volume constant
D to A : adiabatic
VC = VD = 2VA = 2VB
- In which part of the cycle heat is supplied to the engine from outside?
- In which part of the cycle heat is being given to the surrounding by the engine?
- 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?
(γ = `5/3` for the gas), (Cv = `3/2` R for one mole)
Consider one mole of perfect gas in a cylinder of unit cross section with a piston attached (figure). A spring (spring constant k) is attached (unstretched length L) to the piston and to the bottom of the cylinder. Initially the spring is unstretched and the gas is in equilibrium. A certain amount of heat Q is supplied to the gas causing an increase of volume from V0 to V1.
- What is the initial pressure of the system?
- What is the final pressure of the system?
- Using the first law of thermodynamics, write down a relation between Q, Pa, V, Vo and k.
The first law of thermodynamics is concerned with the conservation of ______.
An ideal gas is taken through series of changes ABCA. The amount of work involved in the cycle is ______.
The first law of thermodynamics for isothermal process is ______.
A given system undergoes a change in which the work done by the system equals the decrease in its internal energy. The system must have undergone an ______.
104 J of work is done on a certain volume of a gas. If the gas releases 125 kJ of heat, calculate the change in internal energy of the gas.
In an adiabatic process, ______.
What is Isobaric process?
Obtain an expression for the workdone by a gas in an isothermal process.
Calculate work done when 2 moles of ideal gas expands by 5 dm3 isothermally at pressure 1.2 bar.
Write a short note on isobar.
Define isochoric process
What is an isothermal process?