First Law of Thermodynamics quiz with answers for AP Physics C

📚 Quick Study Guide

• 🔥 The First Law of Thermodynamics states that the change in internal energy ($\Delta U$) of a system is equal to the heat added to the system ($Q$) minus the work done by the system ($W$): $\Delta U = Q - W$.
• 🌡️ Internal energy ($U$) is a state function, meaning it depends only on the current state of the system, not on the path taken to reach that state.
• ⚙️ Work ($W$) done by a gas can be calculated as $W = \int P dV$, where $P$ is the pressure and $V$ is the volume. For a constant pressure process, $W = P\Delta V$.
• 🔄 Heat ($Q$) added to or removed from a system can change its internal energy. Heat can be transferred through conduction, convection, or radiation.
• 🧊 For an adiabatic process, $Q = 0$, so $\Delta U = -W$.
• ♨️ For an isothermal process, $T$ is constant, so $\Delta U = 0$ for an ideal gas, and $Q = W$.
• ⚖️ For an isochoric process, $V$ is constant, so $W = 0$, and $\Delta U = Q$.

Practice Quiz

1. A system absorbs 500 J of heat and performs 200 J of work. What is the change in internal energy of the system?

   1. A) 200 J
   2. B) 300 J
   3. C) 500 J
   4. D) 700 J

2. In an adiabatic process, which of the following is true?

   1. A) Heat transfer is constant
   2. B) Temperature is constant
   3. C) No heat is transferred
   4. D) Volume is constant

3. For an ideal gas undergoing an isothermal process, what is the change in internal energy?

   1. A) Positive
   2. B) Negative
   3. C) Zero
   4. D) Depends on the pressure

4. A gas is compressed at a constant pressure of $2.0 \times 10^5$ Pa from a volume of $1.0 \times 10^{-3}$ m$^3$ to $0.5 \times 10^{-3}$ m$^3$. What is the work done on the gas?

   1. A) -100 J
   2. B) 100 J
   3. C) -200 J
   4. D) 200 J

5. Which of the following processes involves no change in volume?

   1. A) Isobaric
   2. B) Isothermal
   3. C) Adiabatic
   4. D) Isochoric

6. If the internal energy of a system increases by 400 J and the system does 100 J of work, how much heat was added to the system?

   1. A) 300 J
   2. B) 400 J
   3. C) 500 J
   4. D) 600 J

7. In which process is the change in internal energy equal to the heat added to the system?

   1. A) Isobaric
   2. B) Isothermal
   3. C) Adiabatic
   4. D) Isochoric