waves + electricity Flashcards
(25 cards)
types of transverse waves
water, rope, electromagnetic (light, radio)
types of longitudinal waves
ultrasound, seismic, sound
definition of wavelength
shortest distance between any 2 points of a wave that are in phase
definition of amplitude
maximum displacement from rest position
definition of frequency
number of complete waves generated per second
definition of period
time taken to generate one complete wave
formula for period of wave
1 / frequency
formula for speed of wave 1
frequency x wavelength or wavelength / period
definition of electric field
region where an electric force is exerted on any electric charge placed within the influence of the electric field
how to charge 2 insulators
charging by friction
how to charge 1 or 2 conductors
charging by induction
how to discharge an insulator
passing over a flame
how to discharge a conductor
earthing (touch it)
uses of static electricity
photocopying
spray painting
electrostatic precipitator
hazards of static electricity
lightning
fires and explosions
definition of electric current
rate of flow of charge through a given cross-section of a conductor
formula for current
Q/t (charge over time)
definition of emf
work done by an electrical energy source in driving a unit charge around a complete circuit
formula for emf
W/Q (work done/charge)
definition of p.d.
work done in driving a unit charge through a component in a circuit
formula for p.d.
W/Q (work done/charge)
definition of resistance
the ratio of the potential difference across a component to the current flowing through it
formula for resistance
V = IR
define ohm’s law
the current passing through a metallic conductor is directly proportional to the potential difference across it, provided that physical conditions remain constant
