Chapter 4 Flashcards
wave motion
frequency and wavelength
wavelength
- the distances between corresponding points on a wave
- Units: meters/nanometers
frequency
- the number of waves that pass a given point in a specific time
- Units: Hz or 1/s
relation of wavelength and frequency
inversely proportional
relation of wavelength and energy
inversely proportional
relation of frequency and energy
directly proportional
electromagnetic radiation
form of energy that exhibits wavelength behavior as it travels through space
electromagnetic spectrum
all forms of electromagnetic radiation combined
constant velocity
what all types of electromagnetic radiation travel at
speed of light(c)
3.00 x 10^8 m/s
formula for speed of light
c = wavelength x frequency
formula for energy (using frequency)
E = planks constant x frequency
formula for energy (NOT using frequency)
E = (Plancks x speed of light) / wavelength
electromagnetic spectrum in order from least to most energy
Radio
Microwave
Infared
Visible
Ultraviolet
X-ray
Gamma Ray
Visible light travels at what speed
speed of light(c)
Photoelectric effect
- shine light at different metals and they emit electricity
- electricity is only emitted when the frequency of light is high enough
- Light is acting like a particle
- Max Planck came up with it
Who came up with the dual-wave particle theory
Albert Einstein
why were scientists surprised from the photoelectric effect?
They expected that eventually you could shine lower frequency light long enough that enough energy would accumulate but you can’t
quanta
small amounts of energy
photon
a particle of electromagnetic radiation that has zero mass and carries a quantum of energy
planks constant
6.626 x 10^-34 Joules
frequency units
Hz or 1/s
energy unit
Joules or J
ground state
the lowest energy state of an atom
excited state
the higher energy when atoms gain energy, and have a higher potential energy than the ground state
when an excited atom returns to the ground state, it gives off energy in the form of…
electromagnetic radiation
line-emission spectrum
the bands of light that are visible
how are atoms like a fingerprint?
excited atoms exhibit a specific portion of the visible spectrum; unique.
Why do we see distinct colors or different elements?
There are different amounts of energy that is released depending on the frequency
what does Niels Bohr suggest about electrons?
- electrons could circle the nucleus in a fixed path
- electrons could move up and down to higher or lower orbits
absorption
photon is absorbed
electron is emitted
emission
photon is emitted
electron is absorbed
what has to happen for an electron to “jump” from the ground state to an excited state?
Absorption of energy leads to photon getting excited and released a proton
1 meter = ? nanometers
1 x 10^-9 nm
1 kJ = ? J
1000 J
quanta = (Planck constant)(frequency)
TRUE