IMPORTANT EQUATIONS & CONCEPT
T3
Electric and magnetic forces on particles
Direction of moving particles in electric and magnetic fields
can be used to find properties of those particles.
New Vocabulary:
isotope: Each form of the same atom that has the same chemical
properties but a different mass is an isotope.
Mass spectrometer: is an instrument that measures the charge-tomass ratio of positive ions within a material.
Equations:
Charge-to-mass ratio of an electron in a magnetic field.: q/m=v/Br
Charge-to-mass ratio of an ion in a mass spectrometer:
q/m=2Vaccel/B^2r^2
Electric and Magnetic fields in space
Electromagnetic waves are coupled, oscillating electric and
magnetic fields that move through space and interact with
matter.
New Vocabulary:
Electromagnetic waves: are coupled, oscillating electric and magnetic
fields that propagate through space and matter.
Electromagnetic spectrum: is the range of frequencies that make
up the continuum of magnetic waves.
Electromagnetic radiation: is the energy that is carried by
electromagnetic waves in their oscillating electric and magnetic
fields.
Transmitter: is a device that converts voice, music, pics, or data
to electronic signals, amplifies the signals, and then sends the
signals to an antenna.
Antenna: creates the electromagnetic waves that propagate through
the air.
Dielectric: is a poor conductor of electric current whose electric
charges partially align with an electric field.
Carrier wave: is the name of the station in USA a specific
wavelength in the ratio part of the electromagnetic spectrum.
Piezoelectricity: when quartz crystals deform when a potential
difference is applied across them,a property known as
piezoelectricity.
receiver: which converts them to usable information-sound, pics, or
data.
Equations:
√
Wavelength-frequency: λ=c/f & λ=v/f
velocity-of-a-wave: v=c/
k
Interference
Light can interfere when passing through narrow slits or
reflecting from a thin film.
New Vocabulary:
Incoherent light: which is light whose waves are not in phase.
Coherent light: is a light made up of waves of the same
wavelength that are in the phase with each other.
Interference fringes: The overlap created a pattern of bright and
dark bands.
Monochromatic light: which is light of only one wavelength.
Thin-film interference: The colors are a result of the constructive
and destructive interference when light rays reflect from separate
surfaces of a thin film, a phenomenon called thin-film interference.
Equations:
Wavelength from double-slit investigation: λ=xd/L
Diffraction
Light waves diffract when they pass through a single slit
and diffract and interfere when they encounter a diffraction
grating.
New Vocabulary:
Diffraction pattern: is a pattern than causes on a screen when light
passes through a slit that has two closely spaced edges..
Diffraction grating: is a device that is made up of many small
slits that diffract light and form a pattern that is an overlap of
single- slit diffraction patterns..
Rayleigh criterion: states that if the center of the bright spot of
one source's image falls on the first dark ring of the second, the
two images are at the limit of resolution.
Equations:
Width of bright band in single-slit diffraction: 2x1=2λL/w
Wavelenth from a diffraction grating: λ=dsinΘ
Rayleigh criterion: Xobj=1.22λLobj/D
A particle model of waves
Light can behave as massless particles called photons
New Vocabulary:
Emission spectrum: Is a graph of intensity of the radiation
emitted from an object over a range of frequencies.
Quantized: It exists only in bundles of specific amounts.
Photoelectric effect: Is the emission of electrons when
electromagnetic radiation falls on an object.
Threshold frequency: Electrons eject from the cathode only if the
frequency of the incident radiation is greater than a certain
minimum value.
Photon: is a visible light and other forms of electromagnetic
radiation consist of discrete, quantized bundles of energy.
Work function: is the energy needed to free the most weakly bound
electron from the metal.
Compton effect: The shift in the energy of scattered photons.
Equations:
Energy of vibration: E=nhf
Energy of a photon: E=hf
Energy of a photon: E=hc/λ=1240ev.nm/λ
Kinetic energy of an electron ejected due to the photoelectric
effect: KE=hf-hf0
Photon momentum: p=hf/c=h/λ
Matter waves
Moving particles have wavelike properties.
New Vocabulary:
de Broglie wavelength: The wavelength λ calculated from the above
relationship represents that of the moving particle.
Heisenberg uncertainty principle: which states there is a limit to
how precisely a particle;s position and momentum can
simultaneously be measured.
Equations:
De Broglie wavelength: λ=h/p=h/mv
Moza Hilal 12b