Second Law of Thermodynamics Examples
Example 1: If a heat pump works for 600 J and removes 800 J of heat from the low-temperature reservoir. What is the amount of heat delivered to a higher-temperature reservoir?
Solution:
Given,
- W = 600 J
- QC = 800 J
QH =?
Now, according to the laws of thermodynamics.
QH = W + QC
QH = 600 J + 800 J
QH = 1400 J
Thus, heat delivered to the higher temperature reservoir is 1400 J.
Example 2: Find the work done by the heat pump if the heat pump removes 1000 J of heat from high-temperature and delivers 400 J to the low-temperature reservoir.
Solution:
Given,
- QC = 400 J
- QH = 1000 J
W = ?
Now, according to the laws of thermodynamics.
QH = W + QC
1000 J = W + 400 J
W = 1000 – 400
W = 600 J
Thus, work done by the heat pump is 600 J
Example 3: For a reversible heat engine the heat received is 1400 kJ at a temperature of 500K. If the surrounding temperature is 200K then the available amount of heat energy for doing work is?
Solution:
Q1 = 1400 KJ
T1 = 500K
T2 = 200 K
ΔS = Q1 / (T1 + T2)
ΔS = 1400 / (500 + 200)
ΔS = 2 KJ/K
Availability of heat energy for doing work is,
H = Q1 – T2(ΔS)
H = 1400 – 200(2)
H = 1000 KJ
Example 4: For a reversible heat engine the heat received is 1200 KJ at a temperature of 400K and ΔS = 2 KJ/K, then find the temperature of the surrounding.
Solution:
Q1 = 1200 KJ
T1 = 400K
T2 =?
ΔS = 2 KJ/K
We know that,
ΔS = Q1 / (T1 + T2)
2 = 1200 / (400 + T2)
400 + T2 = 600
T2 = 600 – 400 = 200 K
Thus, temperature of the surrounding is 200 K.
Second Law of Thermodynamics
Second Law of Thermodynamics defines that heat cannot move from a reservoir of lower temperature to a reservoir of higher temperature in a cyclic process. The second law of thermodynamics deals with transferring heat naturally from a hotter body to a colder body.
Second Law of Thermodynamics is one of three Laws of Thermodynamics. The word “thermodynamics” comes from two root words: “thermo,” meaning heat, and “dynamic,” meaning power.
This article explores the second law of thermodynamics, along with its different statements, equations for the second law, examples, and applications in real life.
Table of Content
- What is Second Law of Thermodynamics?
- Different Statements of Second Law of Thermodynamics
- Second Law of Thermodynamics Equation
- Perpetual Motion Machine of Second Kind
- Second Law of Thermodynamics: Applications in Real Life
- Limitations of Second Law of Thermodynamics
- Second Law of Thermodynamics Examples