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
Blackbody radiation peaks at a shorter wavelength when the temperature of the object:
Answer: Increases
Wien's displacement law states λ_max = b/T; higher temperature shifts the peak to shorter wavelengths.
An ideal gas undergoes an isothermal expansion. Which of the following is true?
Answer: Heat is absorbed by the gas
In isothermal expansion, ΔU = 0 for an ideal gas, so Q = W > 0; the gas must absorb heat to do work.
Which of the following particles carries a charge of +1e and has a mass of approximately 1 atomic mass unit?
Answer: Proton
A proton carries a charge of +1e and has a mass of approximately 1.67 × 10⁻²⁷ kg, or ~1 amu.
The photoelectric effect provided evidence that light:
Answer: Consists of discrete packets of energy called photons
The photoelectric effect demonstrated that light energy is quantized into photons, each with energy E = hf.
For an isochoric (constant volume) process, the work done by the gas is:
Answer: Zero
At constant volume, ΔV = 0, so W = PΔV = 0; all heat goes into changing internal energy.
In Compton scattering, when an X-ray photon collides with a free electron, the scattered photon has:
Answer: A longer wavelength than the incident photon
The photon transfers some energy to the electron, so the scattered photon has less energy and therefore a longer wavelength.
Which quantum number describes the shape of an electron's orbital?
Answer: Angular momentum quantum number (l)
The angular momentum quantum number l determines the shape of the orbital (s, p, d, f correspond to l = 0, 1, 2, 3).