【正文】 s law: The magnitude of the electrostatic force between two electrically charged bodies is proportional to the product of the charges and inversely proportional to the square of the distance between them.Count rate: The readings on a detector that indicate the average rate of emission of radiation from a radioactive source.Current voltage characteristics: The graph of current I against potential difference V of a circuit ponent.Daughter nucleus: The product of a radioactive decay or a nuclear reaction.De Broglie39。C.Specific latent heat of fusion: the quantity of heat required to change 1 kg of a substance from solid state to liquid state without a change in temperature.Specific latent heat of vaporisation: the quantity of heat required to change 1kg of a liquid to vapour without a change in temperature. Speed: distance travelled per unit time. The SI unit of speed is ms. Speedtime graph: displays the variation of speed of an object with time.Stationary wave: a wave formed by the superposition of two waves which are travelling in opposite directions, and which have the same speed, frequency and amplitudes. The resultant wave stores vibrational energy and its wave profile does not move through the medium but remains stationary.Steady state: the condition reached when the temperature of a body attains a constant value when heat gained by the body is equal to heat lost by the body.Steam point: the temperature of steam maintained at standard atmospheric pressure when it is in thermal equilibrium with pure water.System: a welldefined quantity of matter bounded entirely by a real or imaginary surface.Systematic error: an inherent error in an instrument or in a technique which causes a random set of readings to be distributed consistently around an average that is significantly different from the actual value.Temperature: a measure of the degree of hotness of an object.Terminal speed: the constant speed attained by a body when the upward net force acting on it balances the downward weight as it falls freely through a fluid.Thermal equilibrium: a state in which every part of a body attains the same temperature when heat gained by the body is equal to the heat lost by the body.Thermocouple: a thermometer which uses the electromotive force (emf) generated between two dissimilar junctions to measure a difference in temperature.Transverse waves: progressive waves in which the direction of vibrations of the waves is perpendicular to the line of flow of energy.Trough: the lowest point on a wave.Thermodynamics (first law): the heat ⊿Q transferred to a closed system increases its internal energy ⊿U and causes the system to do work ⊿W on its surroundings during the change.Torque: moment of a couple.Triple point: the single temperature at which pure ice, water, and water vapour coexist together in thermal equilibrium,Uncertainty: the spread of values on either side of a measurement,Vector: a physical quantity which has both magnitude and direction.Velocity: the rate of change of displacement.Velocitytime graph: displays the variation of velocity of an object with time.Wavefront: the crest of a wave or a line that Joins all identical points on a wave with the same phase.Wavelength: the distance between two successive crests or two successive troughs.Work done (by a force on a body): the product of the force and the distance moved in the direction of the force.Zero error the systematic error of a measuring instrument when the scale reading of that instrument does not read exactly zero when there is nothing being measured.Zeroth law of thermodynamics: If two bodies X and Y are separately in thermal equilibrium with a third body T, then X and Y are in thermal equilibrium with each other.Glossary of terms used in Physics ⅡAbsorption line spectra: Dark, vertical and separated lines set against a background of the continuous spectrum of white light.Activity: The number of radioactive disintegrations per unit time.Alpha decay: The spontaneous and random decay of a radioactive nucleus with the emission of an alpha particle.Adiabatic change: The change in pressure, volume and temperature of a system without heat entering or leaving the system.Alpha particle (radiation): A helium nucleus consisting of 2 protons and 2 neutrons. It is emitted from a radioactive nucleus at high speed during an alpha decay.Alternating current: An electric current that varies in magnitude and direction periodically with time. Alternating voltage: An electric voltage that varies in magnitude and direction periodically with time.Ammeter: An instrument that is connected to an electric circuit to measure current, Ampere: The SI unit of electric current. One ampere is equal to one coulomb per second.Archimedes39。s law of gravitation: a point mass will attract another point mass in any part of the universe with a force that is directly proportional to the product of the masses and inversely proportional to the square of the distance between them.Node: a point on a stationary wave where the amplitude of oscillation is zero.Parallax error: arises when the eye is not positioned vertically above the scale to be measured.Parallelogram law of vector addition: the resultant of two vectors acting at a point P is represented by the diagonal of a parallelogram formed by the two vectors and its origin is at F.Path difference: the extra length travelled by a wave when it is pared with another.Period: the time taken to generate a plete wave or to plete one oscillation of a vibrating system.Phase (of a particular point in an oscillation): the fraction of the oscillation measured from an initial chosen point and expressed in degrees (176。s resistance to changes in motion. It is a base quantity with the, SI unit of kilogram.Mean square speed: the average value of the square of the molecular speeds.Measurement: the parison of a physical quantity with a calibrated me