Physics Flashcards
Positron
an anti-electron, denoted beta+ or e+, emitted in a nuclear reaction
Radiation
Form of heat transfer accomplished by electromagnetic waves, which can travel through a vacuum
Capacitor
an electric device used in circuits that is composed of two conducting plates separated by a short distance. When voltage is applied to it, a capacitor stores electric charge
bulk modulus
a term that describes a substance’s resistance to compression under a pressure, denoted by the variable B and measured by the ratio of stress (pressure change) to strain: changeP/(changeV/V)
Fundamental Unit of Charge
the smallest measured electric charge,which belongs to a single proton or electron; this charge is equal to 1.6 X 10^-19 C, and is positive for a proton and negative for an electron
Acceleration
A vector quantity describing a change in velocity over the elapsed time during which that change occurs, expressed as a=changeV/changeT
Velocity
a vector quantity describing an object’s displacement over the elapsed time, expressed as v=changeX/changeT
Potential Difference
the difference in electric potential between two points in an electric field, also termed the voltage (changeV)
Force
a vector quantity describing a push or pull on an object. The SI unit for force is the Newton (N)
Weight
a force that measures the gravitational pull on an object, given by the object’s mass times its gravitational acceleration (mg, where g is 9.8m/s^2 on Earth)
Half-Life
the amount of time it takes for one-half of a radioactive sample to decay, given by the equation t 1/2 = (ln2)/lambda, where lambda is a decay constant
Gamma Decay
the atom emission of high energy photons, also known as y-particles
electric dipole
the effect, often found in chemical bonds, of having two charges of opposite sign and equal magnitude separated by a short distance d
torque
the magnitude of a force acting on a body times the perpendicular distance between the acting force and the axis of rotation, denoted by the Greek letter T with the SI units N*m
Resonance
if a standing wave undergoes a forced oscillation due to an external periodic fore that has a frequency equal to the natural frequency of the oscillating system, resonance will occur, and the amplitude of the standing wave will approach its maximum
Converging Lens
A lens with a thick center that converges light rays at a point where the image is formed
Diverging Lens
a lens with a thin center that diverges light after refraction and always forms a virtual image
Exponential Decay
a decrease in the amount of substance N through radioactive decay, given by the equation: N=N0 X e^-lambdaT
Ferromagnetic
a material whose atoms have net magnetic field and, below a critical temperature, are strongly attracted to a magnet pole
Power
the rate at which work is done, given by the equation P=W/changeT, where W is work and T is time in seconds
Kinetic Energy
the energy of an object resulting from the objects motion through space, calculated by the equation KE =1/2mv^2 and given in the SI unit of Joules (J)
Magnetic Force
a force exerted on a charged particle moving through a magnetic field, calculated using the equation FB = qvBsin0. The sin0 represents the fact that only the component of motion perpendicular to the magnetic field contributes to the magnetic force on the particle
Work Function
The minimum amount of photon energy required to emit an electron form a certain metal. This quantity, denoted by the letter W, is used to calculate the residual kinetic energy of an electron emitted by a metal, given by KE =hf - W, where hf is the energy of a photon
Amplitude
in a wave, the point of maximum displacement from equilibrium