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Level 174

Magnetism


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Magnets/ Greek Origin
Stone from Magnesia, a part of ancient Greece where lodestones were found.
compass
It functions as a pointer to "magnetic north" and aligns itself with the horizontal component of the Earth's magnetic field.
intrinsic
Belonging to the essential nature of a thing
Magnetic Dipole Moment
Matter that shows magnetic behavior has this intrinsic property.
Three levels of dipole moments
Domains, atoms, and electrons (spin)
Magnetic North
The direction a compass needle points (in the northern hemisphere)
Geographic North
True North
monopole
The existence of 1 side of polar opposites without the existence of another.
magnetism
invisible force that acts between a magnet and an object with iron or steel in it.
dipole
Created by equal but opposite charges that are separated by a short distance.
Moving charges
Orbits of electrons spinning around nuclei.
north
North end of a magnet points to Earths geographic_______pole.
south
South end of a magnet points to Earth's geographic _______pole.
Magnetic Domains
Region where the magnetic fields of atoms are aligned.
Electromagnets
A type of magnet whose magnetic field is produced by the flow of electric current.
Where is a bar magnet strongest?
At it's north and south poles.
attract
If opposite poles are brought close together they . . .
repel
If like poles are brought close together they . . .
What's a magnetic field?
A magnetic field is any region of space where magnetic forces can be felt.
What's a magnetic field line?
A line drawn in a magnetic field so that the tangent to it at any point shows the direction of the magnetic field at that point is called a magnetic field line.
Permanent Magnet
a magnet that retains its magnetism after being removed from a magnetic field
Temporary/induced Magnet
An object that loses its magnetism after short time.
ferromagnet
a material that can be turned into a magnet
Difference between magnetic poles and electric charges
magnetic poles cannot exist alone, electric charges can
Gravitational Force
(physics) the force of attraction between all masses in the universe
Uniform Circular motion
A particle moves in a circle with a constant speed
Centripetal Force
A force directed towards the center of a circle that causes an object to follow a circular path
centripetal acceleration
a = centripetal acceleration
Gravitational field
a force field that exists in the space around every mass or group of masses
Tangential
Merely touching; slightly connected; disgressive
Centripetal Force Requirement
An inward force acting upon an object that is moving in a circle, in order to cause its inward acceleration
Gravitational Mass
Mass as used in the law of the universal gravitation; the quantity that measures an object's response to gravitational force
Weightlessness
a condition encountered in free-fall wherein a support force is lacking
Keplers 1st law
each planet orbits the sun in a path called an ellipse with the sun at one focus
Keplers 2nd Law
a line from the planet to the sun sweeps out equal areas of equal intervals of time
Keplers 3rd Law
planets closest to the sun have shorter periods than those further from the sun
Clothoid Loop
a "squashed" loop that evens out the forces on the human body as it travels around it
Natural Satellite
objects that orbit the earth that are not man made - the moon is an example
Man-Made Satellite
a machine that people have put into Earth's orbit to collect information about the universe and solar system using different types of telescopes
Law of Universal Gravitation
a force of gravity that's acts on all objects in the universe
period
The time for one complete pattern of oscilation to take place at any point
F=ma
Force Formula
Electromagnetic Spectrum
a group of different types of waves (radio waves, microwaves, infrared waves, visible light, ultraviolet light, x-rays, gamma rays)
3*10^8
velocity of light all travel at _______m/s
n = c / v
the index of refraction equation
dispersion of light
all the colors of white light when they are refracted - ROYGBIV
blue, green, red
the three primary colors (when combined they produce white)
yellow, cyan (blue), magenta (red)
the three primary pigments (secondary colors)
Transparent
All light passes through; can see through clearly eg. glass
opaque
impossible to see through; preventing the passage of light
reflection of light
light rays will reflect off a surface at the same angle they struck
law of reflection
a scientific law stating that when light reflects off a surface, the angle of incidence always equals the angle of reflection; refers to the predictable behaviour of reflected light
Diffuse reflection
if a surface is rough, the reflected light is sent out in a variety of directions
specular reflection
Reflection of light off a smooth surface
virtual image
a reflected optical image; see "inverted image"
refraction of light
the bending of light as it passes from one medium into another
v =c / n
the formula used for speed of light in other media
Total Internal Reflection
Sin(critical angle)= n2/n1
plane mirrors
flat mirror
concave mirrors
mirror that is curved inwards - has a real focal point
Convex
A mirror whose rays will be reflected and diverge away from each other
rainbows
tiny droplets of water in the sky act as prisms and disperse the light
mirage
An image of a distant object caused by refraction of light as it travels through air of varying temperature.
additive primary colors
Red, blue, and green light. These colors when added together produce white light.
complementary colors
Any two colors that combine to form white light or black pigment.
Line Spectrum
A spectrum that appears as a series of lines when analyzed through a spectroscope.
pigment
A colored substance used to color other materials.
Scatter
When light or sound waves are deflected in multiple directions by other particles or a another vibration.
Spectroscope
An instrument with which light from glowing elements can be analyzed.
spectrum
For sunlight and other white light, the spread of colors seen when the light is passed through a prism or diffraction grating. The colors of the spectrum, in order from lowest frequency (longest wavelength…
subtractive primary colors
The colors of magenta, yellow, and cyan- that, when mixed in certain proportions, reflect any other color in the visible-light part of the electromagnetic spectrum
White Light
A combination of all colors.
electromagnetic wave
a transverse wave that involves the transfer of electric and magnetic energy
electromagnetic radiation
energy that can travel through empty space in the form of waves
Photoelectric effect
Einstein used the results of the photoelectric effect to conclude that a quantum of light acts like a particle- he called them photons.
photon
Packet of light energy (particle of light)
radio waves
electromagnetic waves with the longest wavelength and lowest frequencies
microwaves
electromagnetic waves that can cause water molecules inside food to vibrate, heating the food.
radar
a system that uses reflected waves to detect objects and measure their distance and speed
Infrared rays
have shorter wavelenghts and higher frequencies than microwaves. used for heat lamps in incubators.
thermogram
an image that shows regions of different temperatures in different colors
visible light
electromagnetic waves that can be seen with the unaided eye
ultraviolet rays
electromagnetic waves that can damage or kill living cells, but are needed in small amounts for healthy bones and teeth.
x-rays
electromagnetic waves used to make images of bones and teeth
gamma rays
electromagnetic waves with the shortest wavelength and the highest frequencies
translucent
a type of material that scatters light as it passes through it
primary color
one of three colors that can be used to make any other color
secondary color
any color produced by combining equal amounts of any two primary colors
complementary color
..., A color of light, which when combined with another color of light, produces white light.
ray
..., a straight line extending from a point, used to show how light reflects
regular reflection
..., Reflection that occurs when parallel rays of light hit a smooth surface and all reflect at the same angle
image
..., a copy of an object formed by reflected or refracted rays of light
plane mirror
..., A flat mirror that produces an upright, virtual image the same size as the object
virtual images
..., An upright image formed where rays of light appear to meet or come from. Seen in plane mirrors
concave mirror
..., a mirror with a surface that curves inward
optical axis
..., an imaginary line that divides a mirror in half
focal point
..., the point at which light rays parallel to the optical axis meet when reflected or refracted
real image
`, an image of an object formed by light rays that actually come together at a specific location
convex mirror
..., a mirror with a surface that curves outward
index of refraction
..., a measure of the amount a ray of light bends when it passes from one medium to another
lens
...a curved piece of glass or other transparent material that refracts light.
concave lens
..., a lens that is thinner in the middle than at the edges
convex lens
..., a lens that is thicker in the middle than at the edges
Sound wave
it is a longitudinal wave that is caused by vibrations and that travels through a material medium
medium
A substance through which signals can travel (e.g. air for sound waves).
pitch
frequency is referring to the _______
Doppler effect
is an observed change in the frequency of a wave when the source or observer is moving
loudness
amplitude is referring to the _______
Decibel
is the unit used to measure loudness
Echo
is a reflected sound wave
Echolocation
the process of using reflected sound waves to find objects; used by animals such as bats
Interference
the combination of two or more waves that results in a single wave
Sonic boom
the explosive sound heard when a shock wave from an object traveling faster than the speed of sound reaches a person s ears
standing wave
The resultant of two wave trains of the same wavelength, frequency, and amplitude travelling in opposite directions through the same medium.
Resonance
a phenomenon that occurs when two objects naturally vibrate at the same frequency; the sound produced by one object causes the other object to vibrate
Sound Quality
the result of the blending of several pitches through interference
Noise
a sound that consists of a random mix of frequencies
tinnitus
A ringing in the ears
outer ear
The part of the ear that collects sound waves; consists of the pinna, the ear canal, and the eardrum.
middle ear
The chamber containing three tiny bones (hammer, anvil, and stirrup) that concentrate the vibrations of the eardrum on the cochlea's oval window
inner ear
The innermost part of the ear, containing the cochlea.
oscilloscope
A device used to electronically show the crest and trough of sounds.
ultrasonography
is the use of high frequency sound waves that are beyond the range of normal hearing to produce a record or picture of an organ or tissue,
mechanical waves
A wave that needs a medium to travel through.
Transverse
Side to side axis
Longitudinal
A wave in which the vibration of the medium is parallel to, or in the same direction as, the direction in which the wave travels is called a _______
What is a Wave?
A disturbance that travels from one place to another transporting energy, but not necessarily matter, along with it.
What is a medium
It is the material through
Solids, liquids, and gases
What are 3 types of mediums a mechanical wave can travel through?
Electromagnetic
_______ waves do not need a medium to transfer from one place to another.
amplitude
The _______ of a wave determines the wave energy.
Wavelength
distance between two consecutive crests which are in phase with one another
Frequency
#cycles/second
crest
Points on a wave with maximum displacement
trough
Points on a wave with minimum displacement
Energy
(physics) the capacity of a physical system to do work
Seismic Wave
A vibration that travels through Earth carrying the energy released during an earthquake.
compression
A force that pushes on or squeezes a material.
Rarefactions
The part of a longitudinal wave where the particles of the medium are farther apart.
Why can't sound travel in space?
Space has no medium for the wave to travel on.
wavelength x frequency
formula for wave speed
m/s
A car enters the freeway with a speed of 6.4 m/s and accelerates uniformly for 3.2 km in 3.5 minutes. How fast (in m/s) is the car moving after this time? (units)
m
A car starts from rest and travels for 5.0 s with a constant acceleration of -1.5 m/s^2. How far does the car travel in this time interval? (units)
HZ
frequency is measured in_______