Lecture 4

Question 1

Explain what is meant by an isobaric / isochoric / isothermal process

Answer 1

Isobaric process p = constant
Isochoric process v = constant
Isothermal process T = constant

Question 2

Explain what is meant by an isentropic process

Answer 2

Isentropic process dq = 0

Question 3

Explain what is meant by a cycle process

Answer 3

when a system at a given initial state goes through a
sequence of processes and finally returns to that state, the
system has executed a thermodynamic cycle

Question 4

Define thermal efficiency

Answer 4

𝜂 = 𝑑𝑒𝑠𝑖𝑟𝑒𝑑 𝑜𝑢𝑡𝑝𝑢𝑡 / 𝑟𝑒𝑞𝑢𝑖𝑟𝑒𝑑 𝑖𝑛𝑝𝑢𝑡

Question 5

Give the definitions of the COP for refrigerator and heat pump.

Answer 5

B = Tc/ (Th -Tc)
y = Th/ (Th -Tc)

Question 6

Give one statement of the 2nd law of thermodynamics

Answer 6

Clausius statement:

It is impossible to transfer energy from a cooler to a hotter
body as a sole effect