E,W&P 2 Flashcards
FREQUENCY (f)
number of oscillations per unit time (Hz)
FUNDAMENTAL FREQUENCY
lowest frequency in a harmonic series where a stationary wave forms
FUSE
electrical component designed to break circuit and stop current when a specified amount of current passes through it (safety device)
GPS
global positioning system, network of satellites used to determine an objects position on the Earth’s surface, used in navigation
HARMONICS
whole number multiplesof the fundamental frequency of a stationary wave
INSULATOR
material with a small number density of conduction electrons and a very high resistance
INTENSITY
energy incident per square metre of a surface per second (Wm-2)
INTERFERENCE
addition of two or more waves that results in a new wave pattern (superposition)
INTERNAL RESISTANCE (r)
resistance of a better or cell (ohms)
JOULE
unit of energy 1J = work done to move 1N 1m in direction of the force
KELVIN
SI of temperature (K)
KILOWATT
unit of power (Kw)
KILOWATT- HOUR
3 600 000 J
KIRCHOFF’S 1ST LAW
the sum of the currents entering any junction is always equal to the sum of the currents leaving the junctions
KIRCHOFF’S 2ND LAW
the sum of the e.m.f’s is equal to the sum of the p.d’s in a closed loop
LDR
light dependant resistor- component that changes its resistance with changes in light intensity dark= high resistance, light = low resistance
LED
light emitting diode, only allows electric current to pass through it in one direction &emits light when a p.d is applied across it
LINE SPECTRUM
spectrum produced by a material that contrains only certain frequencies due to electron transitions between energy levels
LONGITUDINAL WAVE
a wave where oscillations are parallel to the direction of wave propagation
MONOCHROMATIC LIGHT
light maves with a single frequency/wavelength
NODE
point tha talways has zero amplitude along a stationary wave due to destructive interference
OHM’S LAW
the electric current through a conductor is proportional to the p.d across it, provided physical conditions remain constant
PHASE DIFFERENCE
the differenceby which one wave leads or lags behing another (radians(rad))
PHOTOCELL
component that reduces its resistance when light shines on it due to the photoelectric emission of electrons
