Free Praxis Physics (5266) Practice Questions

Sample Practice Questions

Try these 10 sample questions from the Praxis Physics (5266) practice bank. Each includes the answer and explanation. Continue with the interactive practice above to review the full question set.

1. 1Two laboratories obtain the same pattern of measurements using a published procedure. Which feature of scientific evidence does this most directly demonstrate?

   1. A.Reproducibility of the evidenceCorrect answer: A
   2. B.Completeness of the explanation
   3. C.Absence of measurement uncertainty
   4. D.Uniqueness of the proposed model

   Explanation: ETS describes scientific knowledge as "Based on experimental evidence that is reproducible". Obtaining the pattern independently supports reproducibility; it does not establish completeness, zero uncertainty, or a unique model.

   Reference: ETS Physics Study Companion — p. 5, Content Topics, Nature of Science, Nature of scientific knowledge, bullet b

2. 2A neutral atom has atomic number 8 and mass number 18. How many neutrons does its nucleus contain?

   1. A.8
   2. B.10Correct answer: B
   3. C.18
   4. D.26

   Explanation: DOE gives "Z + N = A." Therefore N = 18 − 8 = 10. Atomic number counts protons; mass number counts protons plus neutrons.

   Reference: DOE Fundamentals Handbook: Nuclear Physics and Reactor Theory, Volume 1 — Module 1, p. 4, Nuclides

3. 3A rover travels 6 m east and then 8 m north. What is the magnitude of its displacement from its starting point?

   1. A.2 m
   2. B.10 mCorrect answer: B
   3. C.14 m
   4. D.48 m

   Explanation: The handbook states, "the square of the length of the hypotenuse equals the sum of the squares of the lengths of the other two sides." The perpendicular displacement components give √(6² + 8²) = 10 m. Adding the path lengths gives distance traveled, not displacement magnitude.

   Reference: DOE Fundamentals Handbook: Classical Physics — Module 2, p. 23, Review of Mathematical Functions

4. 4Two small objects have positive net charges. When they are brought near each other without touching, what electrostatic interaction occurs?

   1. A.They attract because both have excess protons.
   2. B.They repel because their net charges have the same sign.Correct answer: B
   3. C.They attract because their net charges have the same sign.
   4. D.They exert no force because both charges are positive.

   Explanation: The handbook states, "unlike charges (like electrons and protons) attract each other, and like charges repel each other." Two positive charges therefore repel. A net positive charge does not require protons to have moved between the objects.

   Reference: DOE Fundamentals Handbook: Electrical Science, Volume 1 — Module 1, p. 3, The First Law of Electrostatics

5. 5A bell and a light source operate inside a transparent chamber. Air is gradually removed while both devices continue operating. Why can the light still reach an outside observer while the sound transmission through the chamber interior weakens?

   1. A.Light requires a material medium, whereas sound can cross a vacuum.
   2. B.Both light and sound require material media, but of different densities.
   3. C.Neither light nor sound requires a material medium for propagation.
   4. D.Light can cross a vacuum, whereas sound requires a material medium.Correct answer: D

   Explanation: NASA states, "Electromagnetic waves differ from mechanical waves in that they do not require a medium to propagate." Light is electromagnetic and crosses the evacuated interior; sound is mechanical and loses its transmitting medium as air is removed. The other options reverse, generalize, or deny this distinction.

   Reference: NASA Tour of the Electromagnetic Spectrum — p. 4, What Are Waves? and Electromagnetic Waves

6. 6Reliable new measurements disagree with a long-accepted physical model within the model's claimed domain. What response reflects the nature of scientific knowledge?

   1. A.Retain the model because of its age
   2. B.Reconsider the model using the new evidenceCorrect answer: B
   3. C.Reject the data because the model is accepted
   4. D.Treat acceptance as proof of the model

   Explanation: ETS states, "Major concepts develop and change over time in light of new evidence". Reliable contradictory evidence calls for reassessing the model, regardless of its age or acceptance.

   Reference: ETS Physics Study Companion — p. 5, Content Topics, Nature of Science, Nature of scientific knowledge, bullet c

7. 7Which pair of nuclei represents isotopes of the same element?

   1. A.6 protons, 6 neutrons; 7 protons, 6 neutrons
   2. B.6 protons, 6 neutrons; 6 protons, 8 neutronsCorrect answer: B
   3. C.6 protons, 6 neutrons; 8 protons, 4 neutrons
   4. D.6 protons, 6 neutrons; 5 protons, 7 neutrons

   Explanation: DOE defines isotopes as having "the same atomic number" but differing in neutrons. Only the pair with six protons in both nuclei and different neutron counts meets that condition.

   Reference: DOE Fundamentals Handbook: Nuclear Physics and Reactor Theory, Volume 1 — Module 1, p. 6, Isotopes

8. 8Which description specifies the velocity of a moving train?

   1. A.A train travels a total path length of 20 m each second.
   2. B.A train’s velocity changes northward by 20 m/s each second.
   3. C.A train moves north at a rate of 20 m/s.Correct answer: C
   4. D.A train’s displacement from its starting point is 20 m north.

   Explanation: The handbook defines a vector as "a quantity that has both magnitude and direction." Velocity describes the directional rate of displacement, here 20 m/s north. Path length per time gives speed, velocity change per time gives acceleration, and a directional displacement without a time rate does not specify velocity.

   Reference: DOE Fundamentals Handbook: Classical Physics — Module 2, p. 1, Vector Quantities

9. 9Two point charges exert electrostatic force F on one another. Both charge magnitudes are doubled and their separation is doubled. What is the new force magnitude in the same medium?

   1. A.F/4
   2. B.F/2
   3. C.FCorrect answer: C
   4. D.4F

   Explanation: The handbook states that Coulomb force is "directly proportional to the product of the two charges and inversely proportional to the square of the distance between them". The charge product grows by four and the squared distance by four, so the force magnitude is unchanged.

   Reference: DOE Fundamentals Handbook: Electrical Science, Volume 1 — Module 1, p. 5, Coulomb’s Law, Equation 1-1

10. 10A wave travels to the right along a stretched string while points on the string move up and down. What type of wave is this?

    1. A.A longitudinal wave, because the disturbance travels along the string
    2. B.A transverse wave, because particle motion is perpendicular to propagationCorrect answer: B
    3. C.A longitudinal wave, because particle motion is perpendicular to propagation
    4. D.A standing wave, because string particles oscillate about fixed positions

    Explanation: NASA states, "In a transverse wave, the vibration of the medium is perpendicular to the motion of the wave." The perpendicular displacement makes this transverse. Propagation along the string does not make it longitudinal, and local particle oscillation alone does not establish the fixed node-and-antinode pattern of a standing wave.

    Reference: NASA Toys in Space II: Video Resource Guide — p. 23, Wave Motion