双语物理词汇英语解释ADSATII物理术语词汇PhysicsGlossary.docx

1、双语物理词汇英语解释ADSATII物理术语词汇PhysicsGlossary 双语物理词汇英语解释ADAAbsolute zero The lowest theoretical temperature a material can have, where the molecules that make up the material have no kinetic energy. Absolute zero is reached at 0 K or 273 C.Acceleration A vector quantity defined as the rate of change of the

2、 velocity vector with time.Activity In radioactive substances, the number of nuclei that decay per second. Activity, A, will be larger in large samples of radioactive material, since there will be more nuclei.Alpha decay A form of radioactive decay where a heavy element emits an alpha particle and s

3、ome energy, thus transforming into a lighter, more stable, element.Alpha particle A particle, , which consists of two protons and two neutrons. It is identical to the nucleus of a helium atom and is ejected by heavy particles undergoing alpha decay.Amplitude In reference to oscillation, amplitude is

4、 the maximum displacement of the oscillator from its equilibrium position. Amplitude tells how far an oscillator is swinging back and forth. In periodic motion, amplitude is the maximum displacement in each cycle of a system in periodic motion. The precise definition of amplitude depends on the part

5、icular situation: in the case of a stretched string it would be measured in meters, whereas for sound waves it would be measured in units of pressure.Angle of incidence When a light ray strikes a surface, the angle of incidence is the angle between the incident ray and the normal.Angle of reflection

6、 The angle between a reflected ray and the normal.Angle of refraction The angle between a refracted ray and the line normal to the surface.Angular acceleration A vector quantity, , equal to the rate of change of the angular velocity vector with time. It is typically given in units of rad/s2. Angular

7、 displacement The net change, , in a points angular position, . It is a scalar quantity.Angular frequency A frequency, f, defined as the number of revolutions a rigid body makes in a given time interval. It is a scalar quantity commonly denoted in units of Hertz (Hz) or s1.Angular momentum A vector

8、quantity, L, that is the rotational analogue of linear momentum. For a single particle, the angular momentum is the cross product of the particles displacement from the axis of rotation and the particles linear momentum, . For a rigid body, the angular momentum is a product of the objects moment of

9、inertia, I, and its angular velocity, . Angular period The time, T, required for a rigid body to complete one revolution.Angular position The position, , of an object according to a co-ordinate system measured in s of the angle of the object from a certain origin axis. Conventionally, this origin ax

10、is is the positive x-axis.Angular velocity A vector quantity, , that reflects the change of angular displacement with time, and is typically given in units of rad/s. To find the direction of the angular velocity vector, take your right hand and curl your fingers along the particle or bodys direction

11、 of rotation. Your thumb then points in the direction of the bodys angular velocity.Antinode The points midway between nodes on a standing wave, where the oscillations are largest.Atom The building blocks of all matter, atoms are made up of a nucleus consisting of protons and neutrons, and a number

12、of electrons that orbit the nucleus. An electrically neutral atom has as many protons as it has electrons.Atomic number A number, Z, associated with the number of protons in the nucleus of an atom. Every element can be defined in s of its atomic number, since every atom of a given element has the sa

13、me number of protons.Axis of rotation The line that every particle in the rotating rigid body circles about. BBasis vector A vector of magnitude 1 along one of the coordinate axes. Generally, we take the basis vectors to be and , the vectors of length 1 along the x- and y-axes, respectively.Beats Wh

14、en two waves of slightly different frequencies interfere with one another, they produce a “beating” interference pattern that alternates between constructive (in-phase) and destructive (out-of-phase). In the case of sound waves, this sort of interference makes a “wa-wa-wa” sound, and the frequency o

15、f the beats is equal to the difference in the frequencies of the two interfering waves.Beta decay A form of radioactive decay where a heavy element ejects a beta particle and a neutrino, becoming a lighter element in the process.Beta particle A particle, , identical to an electron. Beta particles ar

16、e ejected from an atom in the process of beta decay.Bohr atomic model A model for the atom developed in 1913 by Niels Bohr. According to this model, the electrons orbiting a nucleus can only orbit at certain particular radii. Excited electrons may jump to a more distant radii and then return to thei

17、r ground state, emitting a photon in the process.Boiling point The temperature at which a material will change phase from liquid to gas or gas to liquid.Boyles Law For a gas held at a constant temperature, pressure and volume are inversely proportional.CCalorie The amount of heat needed to raise the

18、 temperature of one gram of water by one degree Celsius. 1 cal = 4.19 J.Celsius A scale for measuring temperature, defined such that water freezes at 0C and boils at 100C. 0C = 273 K.Center of curvature With spherical mirrors, the center of the sphere of which the mirror is a part. All of the normal

19、s pass through it.Center of mass Given the trajectory of an object or system, the center of mass is the point that has the same acceleration as the object or system as a whole would have if its mass were concentrated at that point. In terms of force, the center of mass is the point at which a given

20、net force acting on a system will produce the same acceleration as if the systems mass were concentrated at that point.Centripetal acceleration The acceleration of a body experiencing uniform circular motion. This acceleration is always directed toward the center of the circle.Centripetal force The

21、force necessary to maintain a body in uniform circular motion. This force is always directed radially toward the center of the circle.Chain reaction The particles and energy released by the fission or fusion of one atom may trigger the fission or fusion of further atoms. In a chain reaction, fission

22、 or fusion is rapidly transferred to a large number of atoms, releasing tremendous amounts of energy.Charless Law For a gas held at constant pressure, temperature and volume are directly proportional.Coefficient of kinetic friction The coefficient of kinetic friction, , for two materials is the cons

23、tant of proportionality between the normal force and the force of kinetic friction. It is always a number between zero and one.Coefficient of linear expansion A coefficient that tells how much a material will expand or contract lengthwise when it is heated or cooled.Coefficient of static friction Th

24、e coefficient of static friction, for two materials is the constant of proportionality between the normal force and the maximum force of static friction. It is always a number between zero and one.Coefficient of volume expansion A coefficient that tells how much the volume of a solid will change whe

25、n it is heated or cooled.Coherent light Light such that all of the associated waves have the same wavelength and are in phase.Collision When objects collide, each object feels a force for a short amount of time. This force imparts an impulse, or changes the momentum of each of the colliding objects.

26、 The momentum of a system is conserved in all kinds of collisions. Kinetic energy is conserved in elastic collisions, but not in inelastic collisions. In a perfectly inelastic collision, the colliding objects stick together after they collide.Completely inelastic collision A collision in which the c

27、olliding particles stick together. Component Any vector can be expressed as the sum of two mutually perpendicular component vectors. Usually, but not always, these components are multiples of the basis vectors, and ; that is, vectors along the x-axis and y-axis. We define these two vectors as the x-

28、 and y-components of the vector. Compression An area of high air pressure that acts as the wave crest for sound waves. The spacing between successive compressions is the wavelength of sound, and the number of successive areas of compression that arrive at the ear per second is the frequency, or pitc

29、h, of the sound.Concave lens Also called a diverging lens, a lens that is thinner in the middle than at the edges. Concave lenses refract light away from a focal point.Concave mirror A mirror that is curved such that its center is farther from the viewer than the edges, such as the front of a spoon.

30、 Concave mirrors reflect light through a focal point.Conduction Heat transfer by molecular collisions.Conservation of Angular Momentum If the net torque acting on a rigid body is zero, then the angular momentum of the body is constant or conserved.Conservation of momentum The principle stating that

31、for any isolated system, linear momentum is constant with time. Constant of proportionality A constant in the numerator of a formula.Constructive interference The amplification of one wave by another, identical wave of the same sign. Two constructively interfering waves are said to be “in phase.”Con

32、vection Heat transfer via the mass movement of molecules.Convex lens Also called a converging lens, a lens that is thicker in the middle than at the edges. Convex lenses refract light through a focal point.Convex mirror A mirror that is curved such that its center is closer to the viewer than the edges, such as a doorknob. Convex mirrors reflect light away from a focal point.Cosine The cosine of an angle in a right triangl