Unit 4 - light and electron trends Flashcards
4 characteristics of waves
Amplitude, wavelength, frequency, speed
amplitude
the height of the waves from the orgin to the peak or crest. this adjusts brightness or intensity of the light - not the type of light itself
wavelength (λ)
the distance from peak to peak (determines the type of light)
frequency (v)
how fast the wave oscillates (determines the type of light), measured in hz, 1/s
speed
the speed of light is constant
formula: 3.00x10^8 m/s
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long wavelength, low frequency, low energy
what is the relationship between wavelength (λ) and frequency (v)
inverse
^^^
short wavelength, high frequency, high energy
formula for wavelength and frequency
speed of light = (wavelength) (frequency)
c=λv
λ - meters
v - 1/s
how would you find the frequency of red light that has a wavelength of 650nm
1 - convert nm to m
2 - plug into the formula v=c/λ
what is the relationship between energy (E) and frequency (v)
direct
which has a shorter wavelength - red or violet light?
violet
formula for energy and frequency
Energy = (Plank’s constant)(frequency)
E = hv
h - plank’s constant
v - 1/s
as the wavelength gets longer, does the frequency get higher or lower?
lower
as the frequency increases, does the energy increase or decrease?
increase
which has a higher frequency - red light or violet light
violet
which is more energetic - red or violet light?
violet
what do you see when you look at sunlight through a spectroscope?
a rainbow/all of the colors (ROYGBIV)
what gas is inside a fluorescent lightbulb
mercury
T or F - every element has its own emission spectra
T
gravitational potential energy
since gravity attracts an object towards earth, an object will store potential energy depending on its height above earth
Electric potential energy
since opposite charges attract (by the electrostatic force), an electron can have stored potential energy depending on how close the electron is to the nucleus
what is potential energy converted into
light
Bohr model of the atom
in an atom, electrons can only exist in distinct energy levels. this means that the energies of the electrons in atoms are quantized
using the emission spectrum of hydrogen, Neils Bohr was able to determine the specific discrete energies that are possible for a single electron to have when in a hydrogen atom
quantized
the possible number of energy values of an electron are negative, electrons reside on specific energy levels
what happens to the electron in hydrogen when electricity is sent through hydrogen gas
1 - the electrons absorb energy from the electricity and they jump up to a higher energy level, gaining potential energy
2 - since the electron is attracted to the nucleus by electrostatic force, the e- falls back down to a lower energy level and releases energy in the form of light