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