CSEC Physics flashcards
CSEC Physics · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Average velocity
- Total displacement divided by total time taken. It is a vector, so it can be zero over a closed loop even when the average speed is not.
- Newton's second law
- The resultant force on a body equals the product of its mass and acceleration, F = ma. Force and acceleration are in the same direction; mass is in kilograms.
- Principle of moments
- A body in rotational equilibrium has the sum of clockwise moments about any point equal to the sum of anticlockwise moments, with no resultant force acting.
- Conservation of momentum
- In a closed system with no net external force, total momentum before an interaction equals total momentum after it. This holds for collisions and explosions in any direction.
- Kinetic energy
- The energy a body possesses because of its motion, given by ½mv². Doubling the speed quadruples the kinetic energy, which is why braking distances rise sharply.
- Terminal velocity
- The constant speed reached when the upward drag on a falling body equals its weight, so the resultant force and acceleration become zero.
- Specific heat capacity
- The energy needed to raise the temperature of one kilogram of a substance by one kelvin, in joules per kilogram per kelvin. For water it is about 4200.
- Specific latent heat
- The energy required to change the state of one kilogram of a substance at constant temperature, without any change in temperature during the change.
- Conduction
- Transfer of thermal energy through a solid by particle vibration and free-electron movement, without bulk movement of the material. Metals conduct well.
- Convection
- Transfer of thermal energy in fluids by currents: warmer, less dense fluid rises and cooler, denser fluid sinks, setting up a circulation. It cannot occur in solids.
- Boyle's law
- For a fixed mass of gas at constant temperature, pressure is inversely proportional to volume, so pV is constant and p₁V₁ = p₂V₂.
- Absolute zero
- The lowest possible temperature, 0 K or about −273 °C, at which particles have minimum kinetic energy. Kelvin temperature equals Celsius temperature plus 273.
- Wave equation
- Wave speed equals frequency multiplied by wavelength, v = fλ. Frequency is fixed by the source; wavelength adjusts when speed changes in a new medium.
- Refractive index
- The ratio of light speed in a vacuum to that in the medium, also equal to sin i divided by sin r for light entering from air.
- Critical angle
- The angle of incidence in the denser medium for which the refracted ray travels along the boundary. Beyond it, total internal reflection occurs; sin C = 1/n.
- Converging lens
- A convex lens that brings parallel rays to a real principal focus. It can form real or virtual images depending on the object distance.
- Diffraction
- The spreading of waves as they pass a gap or edge. It is most noticeable when the gap width is about the same size as the wavelength.
- Ohm's law
- For an ohmic conductor at constant temperature, current is directly proportional to potential difference, V = IR, so its I–V graph is a straight line.
- Resistors in parallel
- Components connected across the same potential difference, so the current divides. The reciprocal of total resistance equals the sum of the reciprocals.
- Electrical power
- The rate of energy transfer in a circuit, given by P = VI, or P = I²R, or P = V²/R, measured in watts.
- Electromotive force
- The energy converted from other forms into electrical energy per unit charge by a source, in volts. It equals terminal voltage plus lost volts.
- Fleming's left-hand rule
- A rule giving the direction of force on a current-carrying conductor in a magnetic field: thumb force, first finger field, second finger current, all mutually perpendicular.
- Electromagnetic induction
- The generation of an electromotive force in a conductor when the magnetic flux linking it changes, for example by moving a magnet near a coil.
- Lenz's law
- The direction of an induced current is such that it opposes the change producing it. This follows from conservation of energy.
- Pressure in a liquid
- Pressure at depth h in a fluid of density ρ is hρg. It depends on depth and density only, not on the shape or width of the container.
- Archimedes' principle
- The upthrust on a body in a fluid equals the weight of fluid it displaces. A floating body therefore displaces its own weight of fluid.
- Hooke's law
- The extension of a spring or wire is directly proportional to the applied force, provided the limit of proportionality is not exceeded. The constant is the spring constant.
- Brownian motion
- The random, jerky movement of small particles suspended in a fluid, caused by uneven collisions with fast-moving molecules. It is evidence for molecular motion.
- Isotopes
- Atoms of the same element with the same number of protons but different numbers of neutrons, so they share chemical properties but differ in mass.
- Alpha decay
- Emission of a helium nucleus from an unstable nucleus, reducing the nucleon number by four and the proton number by two.
- Half-life
- The time taken for half the unstable nuclei in a sample to decay, or for its activity to halve. After n half-lives, one part in 2ⁿ remains.
- Density
- Mass per unit volume, ρ = m/V, measured in kilograms per cubic metre. Relative density compares a substance's density with that of water.