First Law Of Thermodynamics MDCAT Quiz with Answers

The First Law of Thermodynamics is one of the fundamental principles in physics that establishes how energy is conserved in a system. It postulates that energy can neither be created nor destroyed, only transformed from one form to another, or transferred from a system to its environment, or vice versa. For MDCAT students, mastering this law is vital in understanding the transfer of heat, work, and internal energy in thermodynamic processes.

Statement of the First Law
The First Law can be formulated mathematically as:
Δ
????
=
????
−
????
ΔU=Q−W
Here:

Δ
????
ΔU is the change in internal energy of the system.
????
Q is the energy heat added to the system; positive if added and negative if emitted.
????
W is the work done by the system (positive if done by the system, negative if done on the system).
This equation demonstrates that energy added to a system as heat may be used to increase its internal energy or to perform work on the surroundings.

Applications of the First Law
Isothermal Process: In an isothermal process,
Δ
????
=
0
ΔT=0), its internal energy stays put (
Δ
????
=
0
ΔU=0), and the heat added equals the work done:
????
=
????
Q=W

Adiabatic Process: In an adiabatic process (
????
=
0
Q=0), no heat is exchanged with the surroundings, hence the change in internal energy is equal to the negative of work done:
Δ
????
=
−
????
ΔU=−W

Isochoric Process: In an isochoric process (
Δ
????
=
0
ΔV=0), no work is performed (
????
=
0
W=0), so the heat added goes directly to change the internal energy:
Δ
????
=
????
ΔU=Q

Isobaric Process: In an isobaric process (
Δ
∀
=
0
ΔP=0), the heat added does work and also changes the internal energy.

Importance of the First Law
The First Law is important in the explanation of many natural and artificial processes, for example:

Heat engines: The efficiency of engines depends upon the conversion of heat into work through thermodynamic cycles.
Refrigerators: The work is performed on the system, which transfers heat from the colder region to the hotter one.
Biological systems: Cellular processes involve energy transfer, such as converting chemical energy in food to mechanical energy.
MDCAT Quiz: First Law of Thermodynamics
The MDCAT Quiz on the First Law of Thermodynamics mostly contains numerical problems where one has to apply this equation
Δ
????
=
∈
−
????
ΔU=Q−W. There might be conceptual questions regarding thermodynamic processes, energy conservation, and also practical applications, like refrigerators or heat engines.

Free Flashcards for the First Law of Thermodynamics
Free flashcards on the First Law of Thermodynamics can be used by students to rapidly review formulas, key concepts, and the approach to common problem-solving. The flashcards may have examples of thermodynamic processes with questions emphasizing the application of the principle of energy conservation. These resources ensure MDCAT students are well-prepared for thermodynamics-related questions.