Second law of Thermodynamics

Question 1

The second law of TD states that

Answer 1

all processes in nature tend to occur with an increase in entropy and that the direction of change is always such as to lead to the increase in entropy

Question 2

Clausius’ second law

Answer 2

it is not possible to construct a device operating in a cycle whose sole effect is to transfer heat from a body of lower temp to a body of higher temp. Perfect heat engine is impossible!

Question 3

Kelvin-planck’s second law

Answer 3

It is not possible to construct a device operating in a cycle that will convert heat completely to work. Spontaneous flow of heat from a cold body to a hot body would constitute a perfect refrigerator

Question 4

Perpetual motion machines (PMM1)

Answer 4

Perpetual motion machine of the first kind, violates the first law of thermodynamics

Question 5

Perpetual motion machine (PMM2)

Answer 5

Perpetual motion machine of the second kind, a device that violates the second law of thermodynamics

Question 6

Carnot cycle

Answer 6

Theoretical account on heat engines by Nicolas Leonard Sadi Carnot

Question 7

Steps of Carnot cycle

Answer 7

1-2: Reversible isothermal expansion
2-3: Reversible adiabatic expansion
3-4:Reversible isothermal compression
4-1:Reversible adiabatic compression

Question 8

Steps of Reversible Carnot Cycle

Answer 8

1-2: Reversible adiabatic expansion
2-3:Reversible isothermal expansion
3-4:Reversible adiabatic compression
4-1: Reversible isothermal compression

Question 9

Carnot heat engine

Answer 9

A hypothetical engine that operates on the reversible Carnot cycle

Question 10

Carnot refrigerator or heat pump

Answer 10

operates on the reversible reversed Carnot cycle

Question 11

Reversible processes

Answer 11

a process that can be reversed by means of infinitesimal changes in the system, that is, both system and surroundings are returned to their initial states at the end of the process and therefore, such process leaves no trace of any changes in its surroundings.