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_______________physics Matter is a____________________ Light is a _________________.PowerPoint Presentation

_______________physics Matter is a____________________ Light is a _________________.

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_______________physics Matter is a____________________ Light is a _________________.

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_______________physics Matter is a____________________ Light is a _________________.

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- _______________physics
- Matter is a____________________
- Light is a _________________.

Classical

particle

wave

This is "everyday" physics that deals with objects

that are relatively

1. _____________ bigger than _____________

2. _____________ v << _____

large

atoms

slow

c

Einstein

_______________ modified classical physics so that

it would give more accurate results when speeds

_______________________________ and for________________.

His theories are called the ________________ and

________________ Theories of _________________________ .

were close to c

gravity

Special

General

Relativity

Modern

- _______________ physics modified physics to deal with
- _________________________ on the scale of ___________ .
- According to this theory:
- Matter can act like a___________________________.
- Light can act like a___________________________.

atoms

tiny objects

particle or a wave

particle or a wave

Ex: Light in the classical view acts like a ___________

whose _________________ determines its energy:

wave

amplitude

brighter

- _______________
more____________

energy

Ex: The ___________________ effect showed that light

can act like a ______________________ .

photoelectric

particle

shine

light

electrons e-

“photo…”

“…electric”

zinc

Duality:

wave

particle

Einstein _____________________________ for a paper that

explained the photoelectric effect by assuming light

acted like ______________. The higher its _______________

the greater the energy of the light particle. Bright light

consists of ___________ particles.

won a Nobel Prize

frequency

particle

many

dim red

low

_______________ light:

1_______ energy particle

cannot eject an e-

none of these many

_______ energy particles

could eject an e-

low

bright red

________________light:

dim violet

high

________________light:

1_______ energy particle

can eject 1 e-

each of these many

________ energy particles

could eject an e-

high

bright violet

________________light:

The ______________ (basic unit) of electromagnetic

energy (light) is called a _______________ . It has no

mass, but carries ______________ and ________________ .

Its energy is given by:

quantum

photon

energy

momentum

Eph =

where h =

=

Ex: What is the

relationship between

Eph and f?

Eph

f

What quantity does the slope of the line?

See page 1 of Reference Tables

Page 1:

top

The ______________ (basic unit) of electromagnetic

energy (light) is called a _______________ . It has no

mass, but carries ______________ and ________________ .

Its energy is given by:

quantum

photon

energy

momentum

Eph =

hf

where h =

=

Planck's constant

6.63 x 10-34 J·s

Ex: What is the

relationship between

Eph and f?

Eph

f

h

What quantity does the slope of the line?

Eph/f = ?

Ex: What is the relationship between Eph and l?

- Start with the equation:
- Substitute c in for v:
- Solve for f:
- Substitute in the equation for

v = fl

c = fl

f = c/ l

Eph= hf

Eph= hc/l

Ex: What is the

relationship between

Eph and l in graph form?

Eph

l

The greater the wavelength, the ___________ the energy.

Ex: What is the relationship between Eph and l?

- Start with the equation:
- Substitute c in for v:
- Solve for f:
- Substitute in the equation for

v = fl

c = fl

f = c/ l

Eph= hf

Eph= hc/l

Ex: What is the

relationship between

Eph and l in graph form?

Eph

l

less

The greater the wavelength, the ___________ the energy.

Ex: Find the energy of a blue light photon in joules.

Eph = hf = hc/l

= (6.63 x 10-34 J·s) (???)

Convert the answer to electronvolts (eV).

page 1 of RT: 1 eV = ________________ J

Choose f = 6.5 x 1014 Hz

Ex: Find the energy of a blue light photon in joules.

Eph = hf = hc/l

= (6.63 x 10-34 J·s)

(6.5 x 1014 Hz)

= 4.3 x 10-19 J

Convert the answer to electronvolts (eV).

page 1 of RT: 1 eV = ________________ J

Page 1:

top

Ex: Find the energy of a blue light photon in joules.

Eph = hf = hc/l

= (6.63 x 10-34 J·s)

(6.5 x 1014 Hz)

= 4.3 x 10-19 J

Convert the answer to electronvolts (eV).

1.6 x 10-19

See page 1 of RT: 1 eV = ________________ J

_______1 eV_______

1.6 x 10-19 J

Eph = 4.3 x 10-19 J x

Eph = 2.7 eV

_____________ theory - ____________________ energy

is emitted from and absorbed by _______________

in _____________ amounts or ________________ .

( ______________ means "separate, individual pieces.")

Quantum

electromagnetic

matter

discrete

"packets"

Discrete

after:

absorption

before:

Ex: _______________

of a photon

atom has

______ energy

atom

more

emission

Ex: _____________

of a photon

after:

before:

atom has

_______ energy

atom

less

Compton

Ex The ____________Effect: X-rays scatter off electrons.

0

e- at rest KE =____

v=c

before

collision:

x-ray

_______

photon

now has KE

e- ____________

after

collision:

The scattered

photon now has

_______ energy.

So its f is _______

and its l is

______________

less

less

c

longer

momentum

energy

Both _________________and ______________ are conserved.

In sum, light can act like a __________________ or like

a ____________ . Which one it acts like depends on

the situation. When light interacts with..

particle

wave

… __________ , it acts

like a _________________

Examples:

1/ __________________

2/ __________________

… ___________ , it acts

like a __________________

Examples:

1/ __________________

2/ __________________

3/ __________________

light

atoms

wave

particle

interference

absorption

diffraction

emission

collisions

Even when it is described as a photon, we still

use __________ properties such as _______________

and _________________ to describe it.

frequency

wave

wavelength

Electron charge: In 1909, Millikan sprayed drops of

________ into an _______________ field E.

oil

electric

qE

Fe =___

oil drop

mg

Fg =_____

By suspending the oil drop then letting it fall,

he was able to discover that the oil drops always carried

an ___________________________ of the fundamental charge

= ______________________ (the ______________ of charge).

which is the charge on 1 _____________ or _____________ .

Charge is __________________ .

integer multiple

1.6 x 10-19 C

quantum

electron

proton

quantized