Physics questions and solutions

Browse original practice and official past-paper questions. Each question has its own link, with its source and worked solution.

498 questions · Page 11 of 21

1. Q27 · Original practice · 1 mark
   The graph shows magnetic flux density measured at increasing distance from a small magnet. Which statement best describes the data?
   Magnetic fields
2. Q28 · Original practice · 1 mark
   Two laboratories move at constant velocity relative to one another. Each laboratory performs the same mechanics experiment and measures the speed of the same light pulse in vacuum. Which result is consistent with special relativity?
   Special relativity
3. Q29 · Original practice · 1 mark
   A proper time interval is measured by a clock for which the two events occur
   Special relativity
4. Q30 · Original practice · 1 mark
   A spacecraft clock measures a proper time interval of $5.0\,\mu\text{s}$. The spacecraft moves at $0.80c$ relative to Earth. What interval is measured on Earth?
   Special relativity
5. Q31 · Original practice · 1 mark
   A spacecraft has proper length $12.0\,\text{m}$. It passes Earth at $0.60c$. What length is measured by Earth observers?
   Special relativity
6. Q32 · Original practice · 1 mark
   At $0.90c$, the relativistic momentum of a particle is how many times its classical momentum $mv$?
   Special relativity
7. Q33 · Original practice · 1 mark
   The relativity of simultaneity means that two spatially separated events that are simultaneous in one inertial frame
   Special relativity
8. Q34 · Original practice · 1 mark
   Muons have a proper mean lifetime of $2.2\,\mu\text{s}$ and travel at $0.995c$ relative to Earth. Approximately how far can a typical muon travel in Earth’s frame during one dilated lifetime?
   Special relativity
9. Q35 · Original practice · 1 mark
   If $2.0\,\text{mg}$ of mass is completely converted to energy, the energy released is
   Special relativity
10. Q36 · Original practice · 1 mark
    In the twins’ paradox, the travelling twin can return younger than the stay-at-home twin because
    Special relativity
11. Q37 · Original practice · 1 mark
    The graph compares classical and relativistic momentum. Why does the relativistic curve rise increasingly steeply as $v$ approaches $c$?
    Special relativity
12. Q38 · Original practice · 1 mark
    Two idealised blackbody curves are shown. Curve $T_1$ has a shorter peak wavelength than curve $T_2$. Which statement is correct?
    Quantum theory
13. Q39 · Original practice · 1 mark
    What is the energy of a photon of wavelength $500\,\text{nm}$?
    Quantum theory
14. Q40 · Original practice · 1 mark
    Photons of energy $6.0\,\text{eV}$ strike a metal with work function $2.2\,\text{eV}$. The maximum photoelectron kinetic energy is
    Quantum theory
15. Q41 · Original practice · 1 mark
    A metal has work function $2.50\,\text{eV}$. Its threshold frequency is closest to
    Quantum theory
16. Q42 · Original practice · 1 mark
    For a graph of maximum photoelectron kinetic energy against incident frequency, the gradient is equal to
    Quantum theory
17. Q43 · Original practice · 1 mark
    Monochromatic light passes through two narrow slits and a detector screen records alternating bright and dark bands. Which feature of light is most directly demonstrated by this observation?
    Quantum theory
18. Q44 · Original practice · 1 mark
    The diagram shows atomic energy levels and a downward transition $X$. During transition $X$, the atom
    Quantum theory
19. Q45 · Original practice · 1 mark
    For hydrogen, the wavelength emitted in the $n_i=3$ to $n_f=2$ transition is closest to
    Quantum theory
20. Q46 · Original practice · 1 mark
    An electron travels at $2.0\times10^6\,\text{m s}^{-1}$. Its de Broglie wavelength is closest to
    Quantum theory
21. Q47 · Original practice · 1 mark
    Which pair gives evidence for both wave and particle behaviour of light?
    Quantum theory
22. Q48 · Original practice · 1 mark
    A student sorts elementary particles into two groups. Which row contains only quark flavours in the first group and only charged leptons in the second?
    The Standard Model
23. Q49 · Original practice · 1 mark
    Which particle is a lepton?
    The Standard Model
24. Q50 · Original practice · 1 mark
    The gauge boson that mediates the strong nuclear interaction is the
    The Standard Model