Chapter 7 Flashcards
Energy propagated by energetic and magnetic field that increases and then increases in intensity?
electromagnetic radiation
How is electromagnetic radiation described/
by a wave model
What is the wavelength?
What is it represented by?
What is it usually measured in?
distance between the crests of waves
ƛ
nm
What is the frequency?
What is it represented by?
What is it usually measured in?
cycles per second
Greek letter nu (𝜈)
Hertz (Hz) [s^-1]
Relationship between wavelength and frequency?
wavelength increases
frequency decreases
When does the wavelength get more harmful?
the lower it is the more harmful
What is the velocity?
What is it represented by?
What is it usually measured in?
distance a wave can travel per unit time
v
m/s
What is the speed of light?
c = 3.00 x10^8 m/s
What is the equation for velocity?
v = ƛ𝜈
What is the amplitude?
What is it represented by?
What is it usually measured in?
height of crests, depth of troughs
A?
meters
What is amplitude related to?
intensity
What is the relationship between amplitude and intensity/
Amplitude increase, then Intensity increase
What does intensity depend on?
different colors
What causes a change in amplitude?
change in intensity
What is an example of refraction?
rainbows
What is an example of diffraction?
awarenesses that a flashlight is on
Waves travel at different speeds through different media, the transition causes a change in direction?
refraction
Does matter refract or diffract like energy does?
no
Waves bend around the edges of an object?
diffraction
What is blackbody radiation?
an object emitting light when it is heated
As heat is increased to an object, what happens/
the light changes color
What relation does the blackbody radiation show/
relationship between heat & light intensity/wavelength (ƛ)
Who takes the first steps of quantum theory and what did he say?
max planck
objects emit only certain quantities of energy
What equation did plank come up with?
E = nh𝜈
What does each letter stand for in the equation E = nh𝜈 ?
E = energy of radiation
n = the quantum number (positive integer)
h = planks constant
𝜈 = frequency
What is planks contant?
h = 6.626 x10^-34 J x s
What are four major points of planck reasoning?
- objects emit certain quantities of energy
- energy must be emitted by atoms
- atoms must only have certain quantity of energy available to it
- an atoms energy must be quantized
What does quantized mean/
occurring in fixed quantities
When does an atoms energy change?
when it emits or absorbs a quantum
What is the equation for ΔE ?
ΔE = Δ energy absorbed/emitted
ΔE = Δnh𝜈
What is the formula for the smallest possible change in energy?
ΔE = h𝜈
When monochromic light (single wavelength) of a sufficient frequency strikes a metal plate, a current flows with out a time lag?
the photoelectric effect
With the photoelectric effect, for current to flow what must occur?
sufficient frequency
no time lag
What does the threshold frequency change with?
different metals
What is the minimum frequency of light a current requires called?
threshold frequency
What does the classical model of light associate energy with?
associates energy with amplitude instead of frequency
What is the no time lag?
the current flows the moment the light strikes the metal surface
What did Albert Einstein say about light and energy?
light is quantized into bundles of energy
What are the bundles of energy light is quantized into called?
photons
What happens to photons when energy changes?
a photon is absorbed or emitted
What is the E of a photon?
Who said this?
E (photon) = h𝜈 = ΔE (atom)
Albert Einstein
What is the energy of atoms and photons related to and not related to?
related to frequency
not to amplitude
How can an electron not be ejected from the metal by ?
by storying energy from multiple photons
What is the relationship between wavelength and energy?
wavelength decreases, then
energy increases
Scientists saw unique lines across other sections of the electromagnetic spectrum….Who came up with an equation for it?
Johannes Rydberg
1888
What was Rydberg’s equations?
What elements did it work for?
(1/ƛ) = R(H) [(1/n2a) - (1/n2b)]
only H
In Rydberg’s equation what must n be?
n must be an integer
n(a) < n(b)
What is R(H)?
Rydberg’s constant for H
R(H) = 1.096776 x10^7 m^-1
Who made the Bohr model?
Niels Bohr
1915
What was the Bohr model combined ideas of?
planck, einstein, and rydberg