Chp. 6: early quantum theory: the nature of light and matter

What did Hans Geiger and Ernest Marsden measure?
What did their results lead to?

measure the scatting patter of a beam of alpha particles through a thin metal foil
their results led to the discovery of the nucleus

___ is an extension of classical mechanics. It attempts to describe ____

quantum mechanics

matter at the atomic level

Define wavelength

the distance between corresponding points on adjacent waves

what is the speed of light in a vacuum

3.00 x 10^8 m/s

define frequency

the number of waves passing a given point per unit of time

for waves traveling at the same velocity, the longer the wavelength, the ___ the frequency

smaller

What did Isaac Newton beleive?

light consists of beams of particles

Thomas Young shows that light had the ability to...

diffract
this is a wave property

Einstein postulated that light had both ___ and ___

wave and particulate properties

unit for wavelength

nm or nanometers

1 meter = ______ nanometers

10^9

what's the relationship between wavelength and frequency? why?

inversely proportional
speed of light is fixed
as wavelength decreases, frequency increase to maintain the constant

all waves undergo ___ when passing through closely spaced slits, resulting in ___ and ___

all waves undergo diffraction when passing through closely spaced slits, resulting in constructive and destructive interference

When waves constructively interfere, what parameter changes in the resultant wave?
why?

intensity
constructive interference increase the amplitude
wavelength and frequency don't change

all electromagnetic radiation travel at __ velocity

the same

what is the symbol for the speed of light?

c

what is the speed of light?

3.00 x 10^8 m/s

Plank concluded that __ is proportional to __

energy is proportional to frequency

what is planks equation?

E = hv

In Plank's equation what is h? what is v?

h = planks constant = 6.63x10^34J.s
v = frequency

Einstein used Plank's theory to explain ___

photoelectric effect

The minimum energy to release the electron is ___ for __ metals

different for different metals

define a photon

each particle/ packet of light

each photon has an __

energy

define monochromatic light

light consisting of 1 single specific wavelength

define spectrum

radiation w/ many wavelengths

what happens when high voltage is applied to a tube containing a gas at reduced pressure?

the gas emits different colors of light

what is the relationship between energy and frequency? why?

directly proportional
as frequency increases, the total energy increases

what did Bohr apply to the structure of the atom?

he applied the quantized nature of light

electrons travel in ___ around the nucleus in __ orbits

electrons travel in circular around the nucleus in stationary orbits

Bohr developed a model that explains...

atomic photoemission

As an electron absorbs incident energy, it becomes __ and promoted to __

As an electron absorbs incident energy, it becomes excited and promoted to a higher energy state

what happens to the energy when the excited electron relaxes?

it returns to a state of lower energy

electron releases some of its energy in the form of...

electromagnetic radiation

energy is only absorbed or emitted to move an electron from..

one allowed energy state to another

what's the number for h/ planks constant?

6.63x10^-34j-s (joule seconds)

What is the Rydberg constant?

Rh = 2.18 x 10^-18 J

what are ni and nf?

the initial and final energy of the electron

Louise de Broglie suggest that..

matter possesses a wave particle duality

all matter, especially subatomic particles, can be treated as...

a moving wave

limitation of Bohrs model

applied only to the hydrogen atom

Heisenber showed that the more precisely the momentum of a particle is known, the __ precisely its position is known

Heisenber showed that the more precisely the momentum of a particle is known, the less precisely its position is known