PHYSICS Flashcards
wave going from air to water (effect)
refraction
electromagnetic waves used to treat cancer
X-rays and gamma rays have a very high frequency and can kill cancer cells.
angle of incidence equals …
the angle of reflection
part of the electromagnetic spectrum used in television remote controls?
infra-red radiation
The wavefront
is a line joining all the points of a crest of a wave
In circuits, ammeters are always found
in series
In circuits, voltmeters are always found
in parallel.
density formula
mass/volume
electromagnetic waves speed in a vacuum
at 3.0 × 108 m/s
rectangle with a diagonal arrow running
represents variable resistor
Electromagnetic waves are …
transverse waves
Ohm’s law
Ohm’s law states that for a fixed resistance, voltage and current are directly proportional.
electric current
is a measure of the rate of flow of charge.
If the gap is the same size as the wavelength…
it will cause the waves to spread out to their maximum level.
wave speed=
frequency(hertz) × wavelength (m)
total internal reflection occurs
when the angle of incidence is greater than the critical angle.
typical speed for a sound wave travelling in a liquid?
Sound waves travel in water at approximately 1500 m/s.
typical speed for a sound wave travelling in a gas?
Sound waves travel slowest in gases (between 200 and 1000 m/s)
The pitch of a sound can be related to…
FREQUENCY of the sound wave
sound wave travel as…
longitudinal waves through a medium
As you proceed from radio waves to gamma rays across the electromagnetic spectrum, the wavelength will…
decrease
amount of radiation emitted depends on …
surface temperature, colour and texture
condensation
Condensation is the change from a gas to a liquid state. the gas particles lose energy, move more slowly, and they stay close together forming a liquid.
Thermocouples
are used to measure very high temperatures, gives electrical output
brownian motion
the random movement of particles suspended n a liquid or gas, caused by collisions between particles and the molecules of the liquid or gas .
pressure formula
pressure= force(N)/area(m)
Pressure and temperature relationship in gas
as temperature increases, particles in fixed container begin to move faster and faster, increasing collision= increasing pressure
thermal expension
the increase in movement of particles causes objects to become larger as warmed up, (common in metal)
liquid expension
when heated up, particles begin to move faster weakening the intermolecular forces of attraction, and allowing liquid to expand.
thermometer liquid process
in a thermometer, the bulbs heat up the liquid, it expands forcing it to rise
arrangement of particles in expension
gas –> liquid –> solid . because gas has the weakest intermolecular force allowing particles to move further
resistivity
the electrical resistance of a material increases / decreases as it is heated
sensitivity
the smallest change in temperature that a thermometer can measure
range
the difference between highest and lowest temperature the thermometer measures
linearity
the liquid expands the same amount for every celsius increase in temperature
conduction
the process by which heat energy is transmitted through collisions, most important energy transfer in solids.
convection
convection is heat transfer due to a density differential within a fluid. As water’s temperature increases (heat), it become less dense and rise. As it moves up from heat, it cools and becomes more dense and sinks.
radiation
radiation is the emission of energy. it does not require a medium to travel through, mostly travels as waves
the electromagnetic spectrum
is a spectrum of waves created by disturbance in electric and magnetic filed
effect of radiation
surface color absorbs radiation at different rates, surface texture also influences absorption and emits radiation. shiny and smooth reflect= no good absorption
wave motion
the transfer of energy from one point to another
amplitude
is the distance between creast/peak and the center of the wave .
wave length
distance between one crest to another or one trough to another.
frequency
the number of waves produces each second is measured in hertz
transverse waves
transverse waves are formed when the particles vibrate perpendicular to the direction in which the wave is moving
angle of reflection is…
is the angle made between the reflected ray and the normal line
longitudinal waves
are formed when the particles vibrate parralel to the direction in which the wave is travelling .
transverse waves examples
visible light, electromagnetic radiation, ripping along the surface of water, waves formed in shaken rope
longitudinal waves examples
sound waves, waves produced in spring
wave refraction occurs …
when the medium the wave is now traveling through has a different density causing speed to change
diffraction of waves
when a wave passes through a gap, it spread out from the gap . a plane wave will spread ion curved pattern
order of electromagnetic spectrum
radio waves, microwaves, infrared, visible light, ultraviolet, x-rays and gamma rays.
rarefraction
areas of low pressure due to particles being further apart
compression
areas of high pressure due to particles being closer together
pressure
force/area
specific heat
energy/mass x change in energy
pressure
pressure=densityXgravityXdepth
