在sat物理部分考試中，有很多重點詞彙是經常會考到的.。本站小編爲大家精心準備了關於sat物理考試會經常考到的一些詞彙，歡迎大家前來閱讀。
De Broglie wavelength
A wavelength, given by = h/mv, which is associated with matter. Louis de Broglie proposed the idea that matter could be treated as waves in 1923 and applied this theory successfully to small particles like electrons.
Decay constant
A constant, , not to be confused with wavelength, that defines the speed at which a radioactive element undergoes decay. The greater is, the faster the element decays.
Decibel
A logorithmic unit for measuring the volume of sound, which is the square of the amplitude of sound waves.
Deposition
The process by which a gas turns directly into a solid because it cannot exist as a liquid at certain pressures.
Destructive interference
The cancellation of one wave by another wave that is exactly out of phase with the first. Despite the dramatic name of this phenomenon, nothing is “destroyed” by this interference—the two waves emerge intact once they have passed each other.
Diffraction
The bending of light at the corners of objects or as it passes through narrow slits or apertures.
Diffraction grating
A sheet, film, or screen with a pattern of equally spaced slits. Typically the width of the slits and space between them is chosen to generate a particular diffraction pattern.
Direction
The property of a vector that distinguishes it from a scalar: while scalars have only a magnitude, vectors have both a magnitude and a direction. When graphing vectors in the xy-coordinate space, direction is usually given by the angle measured counterclockwise from the x-axis to the vector.
Directly proportional
Two quantities are directly proportional if an increase in one results in a proportional increase in the other, and a decrease in one results in a proportional decrease in the other. In a formula defining a certain quantity, those quantities to which it's directly proportional will appear in the numerator.
Dispersion
The separation of different color light via refraction.
Displacement
A vector quantity, commonly denoted by the vector s, which reflects an object’s change in spatial position. The displacement vector points from the object’s starting position to the object’s current position in space. If an object is moved from point A to point B in space along path AB, the magnitude of the object’s displacement is the separation of points A and B. Note that the path an object takes to get from point A to point B does not figure when deining displacement.
Distance
A scalar quantity. If an object is moved from point A to point B in space along path AB, the distance that the object has traveled is the length of the path AB. Distance is to be contrasted with displacement, which is simply a measure of the distance between points A and B, and doesn’t take into account the path followed between A and B.
Doppler shift
Waves produced by a source that is moving with respect to the observer will seem to have a higher frequency and smaller wavelength if the motion is towards the observer, and a lower frequency and longer wavelength if the motion is away from the observer. The speed of the waves is independent of the motion of the source.
Dot product
A form of vector multiplication, where two vectors are multiplied to produce a scalar. The dot product of two vectors, A and B, is expressed by the equation A · B = AB cos .
sat物理考試常考詞彙：E開頭Efficiency
For a heat engine, the ratio of work done by the engine to heat intake. Efficiency is never 100%.
Elastic collision
A collision in which both kinetic energy and momentum are conserved.
Electric generator
A device that converts mechanical energy to electrical energy by rotating a coil in a magnetic field; sometimes called a “dynamo.”
Electromagnetic induction
The property by which a charge moving in a magnetic field creates an electric field.
Electromagnetic spectrum
The spectrum containing all the different kinds of electromagnetic waves, ranging in wavelength and frequency.
Electromagnetic wave
A transverse traveling wave created by the oscillations of an electric field and a magnetic field. Electromagnetic waves travel at the speed of light, m/s. Examples include microwaves, X rays, and visible light.
Electron
A negatively charged particle that orbits the nucleus of the atom.
Electronvolt
A unit of measurement for energy on atomic levels. 1 eV = J.
Energy
A conserved scalar quantity associated with the state or condition of an object or system of objects. We can roughly define energy as the capacity for an object or system to do work. There are many different types of energy, such as kinetic energy, potential energy, thermal energy, chemical energy, mechanical energy, and electrical energy.
Entropy
The disorder of a system.
Equilibrium
The state of a nonrotating object upon whom the net torque acting is zero.
sat物理考試常考詞彙：S開頭Scalar
A quantity that possesses a magnitude but not a direction. Mass and length are common examples.
Second Law of Thermodynamics
There are a few versions of this law. One is that heat flows spontaneously from hot to cold, but not in the reverse direction. Another is that there is no such thing as a 100% efficient heat engine. A third states that the entropy, or disorder, of a system may increase but will never decrease spontaneously.
Significant digits
The number of digits that have been accurately measured. When combining several measurements in a formula, the resulting calculation can only have as many significant digits as the measurement that has the smallest number of significant digits.
Simple harmonic oscillator
An object that moves about a stable equilibrium point and experiences a restoring force that is directly proportional to the oscillator’s displacement.
Sine
In a right triangle, the sine of a given angle is the length of the side opposite the angle divided by the length of the hypotenuse.
Snell’s Law
Relates the angle of incidence to the angle of refraction: .
Sound
Waves carried by variations in air pressure. The speed of sound waves in air at room temperature and pressure is roughly 343 m/s.
Specific heat
The amount of heat of a material required to raise the temperature of either one kilogram or one gram of that material by one degree Celsius. Different units may be used depending on whether specific heat is measured in s of grams or kilograms, and joules or calories.
Spectroscope
A device that breaks incoming light down into spectral rays, so that one can see the exact wavelength constituents of the light.
Speed
A scalar quantity that tells us how fast an object is moving. It measures the rate of change in distance over time. Speed is to be contrasted with velocity in that there is no direction associated with speed.
Spring
Objects that experience oscillatory or simple harmonic motion when distorted. Their motion is described by Hooke’s Law.
Spring constant
Indicates how “bouncy” or “stiff” a spring is. More specifically, the spring constant, k, is the constant of proportionality between the restoring force exerted by the spring, and the spring’s displacement from equilibrium. The greater the value of k, more resistant the spring is to being displaced.
Standing wave
A wave that interferes with its own reflection so as to produce oscillations which stand still, rather than traveling down the length of the medium. Standing waves on a string with both ends tied down make up the harmonic series.
Static friction
The force between two surfaces that are not moving relative to one another. The force of static friction is parallel to the plane of contact between the two objects and resists the force pushing or pulling on the object.
Strong nuclear force
The force that binds protons and neutrons together in the atomic nucleus.
Sublimation
The process by which a solid turns directly into gas, because it cannot exist as a liquid at a certain pressure.
Superposition
The principle by which the displacements from different waves traveling in the same medium add up. Superposition is the basis for interference.
