A Level Physcis AQA Definations Exam with Questions and Answers (2025-2026)
absolute zero - ✔✔✔-Lowest possible temperature, 0K, object has minimum internal energy.
acceleration - ✔✔✔-Change of velocity per unit time.
activity of radioactive isotope - ✔✔✔-Number of nuclei of the isotope that disintegrate per
second.
amplitude - ✔✔✔-Maximum displacement from equilibrium of oscillating object.
angular displacement - ✔✔✔-Angle an object in circular motion turns through in radians.
angular speed (ω) - ✔✔✔-Rate of change of angular displacement of object in circular motion.
annihilation - ✔✔✔-When a particle and its antiparticle meet, they destroy each other and
become radiation.
antiparticle - ✔✔✔-Equal rest mass and equal and opposite charge to particle.
atomic number - ✔✔✔-Number of protons in nucleus of atom.
Avogadro constant - ✔✔✔-The number of atoms in 12g of carbon-12. Used to define the mole.
back emf - ✔✔✔-The emf induced in the spinning coil of electric motor or in any coil in which
the current is changing. A back emf acts against the change of applied pd.
background radiation - ✔✔✔-Radiation due to naturally occurring substances in the
environment e.g. radon gas, cosmic rays, ground and buildings.
, A Level Physcis AQA Definations Exam with Questions and Answers (2025-2026)
Becquerel (Bq) - ✔✔✔-Unit of radioactive activity, 1Bq = 1 disintegration per second.
binding energy of nucleus - ✔✔✔-Work that must be done to separate a nucleus into its
constituent neutrons and protons.
E = mass defect x c^2
binding energy per nucleon - ✔✔✔-Average work done per nucleon to separate nucleus into
constituent parts.
BE per nucleon = BE of nucleus / mass number.
Boltzmann constant (k) - ✔✔✔-Molar gas constant divided by Avogadro number.
Boyle's law - ✔✔✔-For a fixed mass of gas at a constant temperature, its pressure x volume is
constant. Gases that obey this are an ideal gas.
brittle - ✔✔✔-Snaps without stretching or bending when subject to stress.
Brownian motion - ✔✔✔-Random and unpredictable motion of a particle eg. smoke particles
caused by molecules of the surrounding substance colliding with it. Provided evidence for
existence of atom.
capacitance - ✔✔✔-The charge stored per unit pd of a capacitor. Unit is Farad (F) equal to 1
coulomb per volt. Q = CV.
centre of mass - ✔✔✔-Point through which a single force on the body has no turning effect.
absolute zero - ✔✔✔-Lowest possible temperature, 0K, object has minimum internal energy.
acceleration - ✔✔✔-Change of velocity per unit time.
activity of radioactive isotope - ✔✔✔-Number of nuclei of the isotope that disintegrate per
second.
amplitude - ✔✔✔-Maximum displacement from equilibrium of oscillating object.
angular displacement - ✔✔✔-Angle an object in circular motion turns through in radians.
angular speed (ω) - ✔✔✔-Rate of change of angular displacement of object in circular motion.
annihilation - ✔✔✔-When a particle and its antiparticle meet, they destroy each other and
become radiation.
antiparticle - ✔✔✔-Equal rest mass and equal and opposite charge to particle.
atomic number - ✔✔✔-Number of protons in nucleus of atom.
Avogadro constant - ✔✔✔-The number of atoms in 12g of carbon-12. Used to define the mole.
back emf - ✔✔✔-The emf induced in the spinning coil of electric motor or in any coil in which
the current is changing. A back emf acts against the change of applied pd.
background radiation - ✔✔✔-Radiation due to naturally occurring substances in the
environment e.g. radon gas, cosmic rays, ground and buildings.
, A Level Physcis AQA Definations Exam with Questions and Answers (2025-2026)
Becquerel (Bq) - ✔✔✔-Unit of radioactive activity, 1Bq = 1 disintegration per second.
binding energy of nucleus - ✔✔✔-Work that must be done to separate a nucleus into its
constituent neutrons and protons.
E = mass defect x c^2
binding energy per nucleon - ✔✔✔-Average work done per nucleon to separate nucleus into
constituent parts.
BE per nucleon = BE of nucleus / mass number.
Boltzmann constant (k) - ✔✔✔-Molar gas constant divided by Avogadro number.
Boyle's law - ✔✔✔-For a fixed mass of gas at a constant temperature, its pressure x volume is
constant. Gases that obey this are an ideal gas.
brittle - ✔✔✔-Snaps without stretching or bending when subject to stress.
Brownian motion - ✔✔✔-Random and unpredictable motion of a particle eg. smoke particles
caused by molecules of the surrounding substance colliding with it. Provided evidence for
existence of atom.
capacitance - ✔✔✔-The charge stored per unit pd of a capacitor. Unit is Farad (F) equal to 1
coulomb per volt. Q = CV.
centre of mass - ✔✔✔-Point through which a single force on the body has no turning effect.
