topic 5

Question 1

What is a progressive wave

Answer 1

Waves have energy

Question 2

What is Displacement

Answer 2

The position on a wave at a point in time, distance from equilibrium

Question 3

What is amplitude

Answer 3

Magnitude of maximum displacement

Question 4

What is frequency

Answer 4

The amount of full wavelengths that pass a point in a second

Question 5

What is wavelength

Answer 5

The distance between two of the same points on a wave

Question 6

What is period

Answer 6

The time taken for a complete wavelength to pass a point

Question 7

What is phase

Answer 7

A point on a compete cycle in radians

Question 8

What is superposition

Answer 8

The resultant amplitude from two waves interfering with each other

Question 9

What are coherent waves

Answer 9

Waves with the same f and phase relationship is constant

Question 10

How many nodes does a fundamental wave have

Answer 10

2nodes one anti-node

Question 11

What is diffraction

Answer 11

When a waves passes through a gap with similar wavelength it will spread out into the space behind the object

Question 12

How to find grating space

Answer 12

1*10^-3/number per mm

Question 13

What is refraction

Answer 13

When a wave enters a medium of different density at an angle and changes direction and velocity

Question 14

What is polarisation

Answer 14

When waves only oscillate in one plane

Question 15

Can mediums polarise light?

Answer 15

Yes

Question 16

What is path difference

Answer 16

The difference in wavelength between two waves

Question 17

When is total internal reflection

Answer 17

When angle is greater than the critical angle

Question 18

What is a real image

Answer 18

Can be projected onto a screen

On opposite side of the lens from the object

Question 19

What is virtual image

Answer 19

Cannot be projected

Is on the same side of the lens as the object

Question 20

What happens to the light in a convex lens

Answer 20

Light bends inwards

Question 21

What happens to the light in a diverging lens

Answer 21

Light bends outwards

Question 22

What are the properties of an electromagnetic wave

Answer 22

can travel through a vacuum
Can be reflected, refracted and defracted
Travels at a speed of light

Question 23

What is a wave front

Answer 23

An imaginary plane joining points on two or more waves in phase

Question 24

What is Huygens construction

Answer 24

each particle from a secondary wave front can be sources for secondary wavelets and form a new wave front

Question 25

What is the formula for critical angle

Answer 25

Sin(C)=1/n

Question 26

What is evidence for light as a wave

Answer 26

Diffraction grating = interference and polarisation

Question 27

What is the evidence of light as a particle

Answer 27

Photoelectric effect

Question 28

What is the photoelectric effect

Answer 28

Light exists as pockets of energy called photons

Question 29

Why is planks constant used and what is quantisation

Answer 29

The minimal possible energy required to jump an energy level called quantisation

Question 30

Evidence for electron as wave

Answer 30

diffraction and interference

Question 31

Evidence for electron as a particle

Answer 31

Ionisation

Question 32

What is wave particle duality

Answer 32

When something can act as a particle or a wave depending on the circumstances

Question 33

What is the work function

Answer 33

The minimal energy required for electrons to leave a surface oof a material

Question 34

What are photoelectrons

Answer 34

When electrons leave the surface of a metal

Question 35

Do particles have a threshold frequency

Answer 35

Yes

Question 36

What equation can be combined with Kinetic energy equation

Answer 36

1/2mv^2(max) = hf-Ф

Question 37

What is the stopping voltage, and how does this relate to kinetic energy equation

Answer 37

The voltage required to attract all the photoelectrons back into the surface of a metal. 1/2mv^2 (max)= exV(s)

Question 38

How can the work function equation be related to a graph

Answer 38

Ek=hf-Ф | y=mx+c

Question 39

What is the ground state and what n is it

Answer 39

The lowest energy level an electron can be at | n=1

Question 40

How do electrons get exited

Answer 40

If a photon with enough energy

Question 41

How do electrons get exited

Answer 41

If a photon with enough energy collides with it

Question 42

How do electrons get exited

Answer 42

If a photon with enough energy and correct frequency collides with it

Question 43

How do electrons get exited in a gas

Answer 43

In gas with enough energy some wavelengths of light will be absorbed by the electrons

Question 44

Do electrons de-excite on their own

Answer 44

Yes they will drop an energy level

Question 45

How do you know when an electron has left a atom

Answer 45

When the diagram has an energy level of 0 mening the electron has left and ionised the atom

Question 46

What is the ionisation energy

Answer 46

The amount of energy required for an electron to leave an atom

Question 47

What is a line spectra and how is it made

Answer 47

Diffraction grating is used to spread out the different wavelengths of light and displaying them on a black sheet.

Question 48

How can a gas line spectra be seen

Answer 48

Gas is heated up and looked at through a diffraction grating so the lines can be seen Each line is shown because of electrons dropping between two energy levels

Question 49

What is intensity

Answer 49

The amount of energy needed per unit area and per unit time