Photons and Lasers

Question 1

What is light made of

Answer 1

Photons

Question 2

What is discrete data

Answer 2

Data that you can physically count like shoe size, its a set scale

Question 3

Does radiation come in discrete or continuous packets.

Answer 3

Discrete

Question 4

How do you find the energy of a photon

Answer 4

E = hf

Question 5

What is h

Answer 5

Planck’s Constant
6.63x10^-34

Question 6

What is an ev

Answer 6

Electron volt is the energy transferred when an electron moves between two points
1ev = 1.6x10^-19

Question 7

What are progressive waves

Answer 7

Pattern of disturbances travelling through a medium and carrying energy with it

Question 8

If you shine a UV light on a negatively charged plate, what happens with the gold leaf

Answer 8

It falls

Question 9

If you shine a UV light on a positively charged plate, what happens with the gold leaf

Answer 9

No effect

Question 10

What is the symbol for work function

Answer 10

Φ

Question 11

What is threshold frequency

Answer 11

The minimum energy required for the photoelectric effect to happen

Question 12

What is the unit for Work function

Answer 12

J or eV

Question 13

What is the formula for work function

Answer 13

Ekmax = hf - Φ

Question 14

If electrons are emmited, is there any time delay

Answer 14

No

Question 15

If electrons are emitted, the _____ of electrons emitted per second is proportional to the _______ of the radiation

Answer 15

Number, Intesity

Question 16

Are waves Particles or waves

Answer 16

Both lol

Question 17

What is particle wave duality

Answer 17

That waves are both particles and waves

Question 18

What does it mean when am atom is excited

Answer 18

Absorbs an energy and goes up one level

Question 19

What is de-excitation

Answer 19

When an atom loses and energy and drops a level

Question 20

What is minimum ionisation energy of an atom

Answer 20

Its the energy required for an atom to be moved from its ground state

Question 21

What is the bottom floor of the energy spectrum called

Answer 21

Ground State

Question 22

Explain the emission spectrum

Answer 22

Different atoms have different energy levels, they emit different photons when de-exciting and each colour has its own energy so it will produce that colour

Question 23

What is absorption spectrum

Answer 23

When An atom absorbs a proton, they will produce different energies and therefore will emit different colours

Question 24

What is the equation for photon energy

Answer 24

E=hc/λ

Question 25

What was the wave particle duality practical using the electron beam gun

Answer 25

Shoot electrons through a double slit, it doesnt come out as singular lines, nor as a solid wave, its just a lot of dots in the shape of a wave

Question 26

What is De Broglie equation

Answer 26

λ = h/p where p is momentum and h is plancks constant

Question 27

What is Einsteins Equation

Answer 27

E=mc^2

Question 28

What does laser stand for

Answer 28

Light Amplification by Stimulated Emission of Radiation

Question 29

What is population inversion

Answer 29

When we promote half of the electrons to a higher level

Question 30

Why wont a two level laser system work

Answer 30

Because through population inversion we can only get 50% off the ground layer and that is not enough

Question 31

How does stimulated emission work

Answer 31

When a photon passes by an electron at Level 1, it causes the electron to drop to Lg and emit a photon, that photon is travelling in the same plane of polarisation as the stimulating photon

Question 32

Why is level 4 more efficient than level 3

Answer 32

Because it has barely any time to spend at Level g because it will be pumped.

Question 33

Define prompt drop

Answer 33

When the electron quickly drops down a level

Question 34

Define Pumping

Answer 34

When electrons get excited all the way from the bottom level to the top level

Question 35

True or false, Can we have clones of photons

Answer 35

True

Question 36

What does it mean to have a photon clone

Answer 36

It has the same frequency, plane of polarisation, in phase and same direcetion

Question 37

Is a laser light coherent

Answer 37

True

Question 38

How many times can a photon be cloned

Answer 38

Theoretically an infinite amount of time

Question 39

What are the uses of a semiconductor (diode) Laser

Answer 39

Scanning barcodes, Laser printing, Scanning DVD's

Question 40

What is the metastable state

Answer 40

A state in which electrons spend, on average, a long time before spontaneously falling

Question 41

Define what spontaneous mean

Answer 41

At random, there is no stimulus or reason why they fall in that exact moment

Question 42

What is the efficiency on average of a conventional laser

Answer 42

1%

Question 43

What are advantages of diode lasers

Answer 43

They are smaller, cheaper and more efficient

Question 44

What are advantages of conventional lasers

Answer 44

More powerful and more exact and precise