Thermo

Question 1

What is thermodynamics?

Answer 1

The study of processes in which energy is transferred as heat and as work.

Question 2

What is the 0th law of thermodynamics?

Answer 2

When 2 objects are in thermal equilibrium separately with a 3rd object then they are in thermal equilibrium with each other
T1 = T2 and T2 = T3  T1 = T3

Question 3

What is thermal equilibrium?

Answer 3

Thermal equilibrium means there is no net thermal energy flow between the objects

Question 4

How do you calculate thermal equilibrium?

Answer 4

-Qlost = Qgained (WHERE Q LOST IS HOTTER AND GAINED IS COOLER)

Question 5

What is the first law of thermodynamics?

Answer 5

The First Law of Thermodynamics states that energy cannot be created or destroyed, only transferred as heat or work

U = Q + W

Question 6

What are all the conventions (POSITIVES AND NEGATIVES) for U = Q + W?

Answer 6

+Q denotes thermal energy absorbed by the gas
-Q stands for thermal energy lost by the gas
+W stands for work done by the gas (the gas is expanding)
-W stands for work done on the gas (the gas is being compressed)
+U represents an increase in temperature
-U represents an decrease in temperature

Question 7

What is the formula for work in a heat engine?

Answer 7

W = Q2 - Q1:
where q2 is the heat energy absorbed by the engine and q1 is the energy released by the engine

Question 8

What is thermal efficiency of an engine?

Answer 8

The thermal efficiency (Eff) of an engine therefore is the ratio of the work it does W to the heat input (simply work as a %).

efficiency = output/input * 100