Physics: Thermodynamics & Modern Physics Flashcards
7 cards from real AP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Physics: Thermodynamics & Modern Physics flashcards as text
According to de Broglie's hypothesis, what is the wavelength of a particle with momentum p?
Answer: λ = h/p
De Broglie's relation gives the matter wavelength as λ = h/p, where h is Planck's constant.
In nuclear fission, when a heavy nucleus splits, the products have:
Answer: Less total mass than the original nucleus
Mass-energy equivalence (E=mc²) means the mass defect is converted to kinetic energy of the fragments.
A gas expands adiabatically against zero external pressure (free expansion). What is true?
Answer: Both Q and W equal zero
In free expansion, no heat is exchanged (adiabatic) and no work is done (P_ext = 0), so Q = W = 0 and ΔU = 0.
The Heisenberg Uncertainty Principle states that:
Answer: The position and momentum of a particle cannot both be precisely known simultaneously
Heisenberg's principle states Δx·Δp ≥ ℏ/2, meaning precise knowledge of position limits precision of momentum and vice versa.
Which process results in a net decrease in entropy of the universe?
Answer: No real process can cause a net decrease in entropy of the universe
The Second Law of Thermodynamics prohibits any process from decreasing the total entropy of the universe.
In beta-minus decay, a neutron transforms into:
Answer: A proton, an electron, and an antineutrino
Beta-minus decay: n → p + e⁻ + ν̄_e; the nucleus emits an electron and an electron antineutrino.
A heat pump moves 1500 J of heat from a cold reservoir to a hot reservoir by using 500 J of work. What is the COP (coefficient of performance) of this heat pump?
Answer: 3.0
COP of a heat pump = Q_hot / W = 1500 J / 500 J = 3.0.