AP Physics 2: Algebra-Based Practice Quiz: Quantum Theory and Wave-Particle Duality
Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026
Test your understanding with short quizzes. This quiz has 10 questions to check your progress.
Question 1 of 10
All Questions (10)
A) To confirm the predictions made by classical mechanics.
B) To explain observations of matter and energy that classical mechanics could not.
C) To describe the motion of large-scale objects like planets.
D) To unify the theories of gravity and electromagnetism.
Correct Answer: B
The text explicitly states, 'Quantum theory was developed to explain observations of matter and energy that could not be explained using classical mechanics.'
A) A particle with a positive charge and significant mass.
B) A massless, electrically neutral particle.
C) A particle whose energy is inversely proportional to its frequency.
D) A massive particle that carries a negative charge.
Correct Answer: B
The text describes a photon as a 'massless, electrically neutral particle.' The other options contradict this description.
A) Its energy is halved.
B) Its energy is doubled.
C) Its energy is quadrupled.
D) Its energy remains the same.
Correct Answer: B
The equation E = hf shows a direct linear relationship between energy (E) and frequency (f). Therefore, if the frequency is doubled, the energy must also be doubled.
A) The wavelength is directly proportional to the momentum.
B) The wavelength is inversely proportional to the momentum.
C) The wavelength is proportional to the square of the momentum.
D) There is no relationship between wavelength and momentum.
Correct Answer: B
The text states that the de Broglie wavelength 'increases as the momentum of a particle decreases.' This describes an inverse relationship, which is also shown by the equation λ = h/p.
A) It will be reduced to one-third of its original value.
B) It will remain unchanged.
C) It will triple.
D) It will increase by a factor of nine.
Correct Answer: C
Based on the equation λ = h/p, wavelength (λ) and momentum (p) are inversely proportional. If momentum (p) becomes p/3, the new wavelength will be h/(p/3), which simplifies to 3 * (h/p), or three times the original wavelength.
A) Photon A has less energy than Photon B.
B) Photon A has the same energy as Photon B.
C) Photon A has more energy than Photon B.
D) The energy of the photons cannot be determined from their frequency.
Correct Answer: C
The relationship E = hf indicates that energy is directly proportional to frequency. Since Photon A has a higher frequency, it must have more energy than Photon B.
A) The electron has a shorter wavelength.
B) The electron has a longer wavelength.
C) The electron and the proton have the same wavelength.
D) The wavelength depends on charge, not momentum.
Correct Answer: B
The de Broglie wavelength (λ) is inversely proportional to momentum (p), as given by λ = h/p. Since the electron has less momentum, it will have a longer de Broglie wavelength.
A) Increase the momentum of the particle.
B) Decrease the momentum of the particle.
C) Add electric charge to the particle.
D) Keep the momentum of the particle constant.
Correct Answer: B
The provided text and equation (λ = h/p) state that the de Broglie wavelength increases as the momentum of a particle decreases. Therefore, to increase the wavelength, the momentum must be decreased.
A) A baseball following a parabolic trajectory when thrown.
B) A planet orbiting the sun due to gravitational forces.
C) An electron with a specific momentum also having a quantifiable wavelength.
D) The constant energy of a photon regardless of its frequency.
Correct Answer: C
The concept of wave-particle duality, as described in the text, means an object has both particle properties (like momentum) and wave properties (like wavelength). An electron having both momentum and a de Broglie wavelength is the prime example of this among the choices. Options A and B are described by classical mechanics.
A) Phenomenon 1: λ = h/p, Phenomenon 2: E = hf
B) Both phenomena are described by E = hf.
C) Phenomenon 1: E = hf, Phenomenon 2: λ = h/p
D) Both phenomena are described by λ = h/p.
Correct Answer: C
The text explicitly links the energy of a photon to its frequency with E = hf. It links the wave model of matter (like an electron) to its momentum with the de Broglie wavelength equation, λ = h/p. Therefore, C correctly matches each phenomenon with its corresponding equation.