Exam 2 Lecture 5

Question 1

Define A “quantum”

Answer 1

the smallest quantity or packet of a given form of electromagnetic radiation

Question 2

Quantum Effects

Answer 2

1900: Max Planck

Energy is released/absorbed only in discrete “units”, “packets”, or “quanta”

Question 3

Planck’s Constant

Answer 3

h=6.62607004 × 10-34 m² kg / s

Question 4

the photoelectron effect

Answer 4

Einstein

refers to the emission, or ejection, of electrons from the surface of, generally, a metal in response to incident light.

Question 5

Einstein’s photons

Answer 5

Electromagnetic radiation behaves as if composed of a stream of particles, or “photons”

Question 6

energy of 1 photon

Answer 6

The energy of one “photon” = the energy of one “quantum”

Question 7

Light behaving as a wave

Answer 7

Question 8

LIght behaving as a particle

Answer 8

Question 9

Light behaving as both a wave and a particle:

Answer 9

Question 10

Two things are quantized

Explain why

Answer 10

matter and energy

There isn’t such a thing as half an H atom

There isn’t such a thing as half a photon

Question 11

Formula for energy of a photon

Answer 11

E=nhv

n=number of photons

h=6.62607004 × 10-34 m² kg / s

v=frequency in hertz (or 1/s)

Question 12

Energy of a single photon

Answer 12

E=hv

h=6.62607004 × 10-34 m² kg / s

v=frequency in (1/s)

Question 13

emission specrtrum

Answer 13

a spectrum of the electromagnetic radiation emitted by a source.

Question 14

absorbtion spectrum

Answer 14

a spectrum of electromagnetic radiation transmitted through a substance, showing dark lines or bands due to absorption of specific wavelengths.

Question 15

line spectrum

Answer 15

an emission spectrum consisting of separate isolated lines.

Question 16

Who is this?

Answer 16

Niels Bohr

Question 17

What did Bohr do?

Answer 17

He made a model for the hydrogen atom

Question 18

Monochromatic light:

Answer 18

light (radiation) of a single wavelength (ex.: laser light)

Question 19

Visible light:

Answer 19

composed of light (radiation) of many different wavelengths

Question 20

What gives rise to all of the color that we observe?

Answer 20

Electron excitation and relaxation

Question 21

The heat of the flame ___________. When the electron ______back to the _______, energy is released as visible light.

Answer 21

excites an electron to a higher energy state

relaxes

“ground state”

Question 22

Calculate energy with wavelength

Answer 22

Question 23

What happens to a line spectra when you shine visible light through a prism?

Answer 23

It reveals the colors involved

Question 24

Name Bohr’s postulates

Answer 24

Question 25

Bohr’s postulates

1. Only electron “orbits” of certain energies are allowed (the energy of an e - are allowed (the energy of an e is quantized)
2. An electron in a An electron in a “permitted orbit permitted orbit ” has a specific energy (an allowed energy “state”)
3. _______

Answer 25

An electron in an allowed state is stable An electron in an allowed state is stable and will not radiate energy

Question 26

Bohr’s postulates

1. Only electron “orbits” of certain energies are allowed (the energy of an e - are allowed (the energy of an e is quantized)
2. ________
3. An electron in an allowed state is stable An electron in an allowed state is stable and will not radiate energy

Answer 26

2 An electron in a An electron in a “permitted orbit permitted orbit ” has a specific energy (an allowed energy “state”)

Question 27

Bohr’s postulates

1. ____________
2. An electron in a An electron in a “permitted orbit permitted orbit ” has a specific energy (an allowed energy “state”)
3. An electron in an allowed state is stable An electron in an allowed state is stable and will not radiate energy

Answer 27

Only electron “orbits” of certain energies are allowed (the energy of an e - are allowed (the energy of an e is quantized)

Question 28

n=1 is what state

Answer 28

Question 29

n>1 is what state?

Answer 29

Question 30

n=1 is what state

Answer 30