Chapter 4.5 - Quantum Physics Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

Photon model

A

Light is made of many particles called photons, each of which is a quantum of light energy. A photon will either transfer all or none of its energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Energy of a photon

A

E=hf

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Electronvolt

A

The kinetic energy gained by an electron when it is accelerated through a p.d. of 1 volt

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Experiment to determine planck’s constant

A

Connect an LED in series with a variable resistor and in parallel with a voltmeter. Adjust the variable resistor so that only a tiny amount of light is being emitted by the LED. Record the threshold voltage and the wavelength of the light being emitted. Do this with different LEDs of different wavelengths. Plot V against 1/λ and the gradient should be hc/e.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Why the experiment to determine Planck’s constant works

A

All of the kinetic energy of the electron is transferred to a photon, therefore we can equate the two values

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

The photoelectric effect

A

Shining E.M radiation on a metal will instantaneously eject photoelectrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Experiment to show photoelectric effect

A

A plate with a gold leaf attached is negatively charged. UV light is shone onto the plate and the photons are ejected, meaning that the gold leaf is no longer repelled and will fall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Significance of the photoelectric effect

A

Evidence for the particulate nature of light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Photoelectric equation

A

hf = φ + KE(max)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Work function

A

The energy needed to eject an electron with 0 KE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Threshold frequency

A

The minimum frequency at which photoelectrons will be emitted. hf = φ + KE (max)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How is intensity related to maximum KE of ejected electrons

A

Independent (not related)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How is the rate of emitted electrons related to intensity

A

Proportional

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Evidence for wave like behaviour of particles

A

Electron diffract through the gaps between atoms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Materials that electrons are diffracted through

A

Polycrystalline graphite

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

De broglie equation

A

λ = h/p

where p is momentum