H Physics Particles & Waves

Question 1

What is the Standard Model?

Answer 1

The Standard Model refers to the best ‘model’ of matter we have from current research based on the particles things are made from and how they interact. It also describes and explains three of the four known fundamental forces: the strong nuclear force, the weak nuclear force and the electromagnetic force. It doesn’t describe or explain gravity.

Question 2

What types of particles are in the standard model?

Answer 2

Leptons and Quarks

Question 3

Name some leptons

Answer 3

Electron. Electron Neutrino. Muon. Muon N.. Tau, Tau N…

Question 4

Name some quarks

Answer 4

Up Down, Charm, Strange, Top, Bottom

Question 5

What are the 1st generation Quarks?

Answer 5

Up, Down

Question 6

What are the 1st generation Leptons?

Answer 6

Electron. Electron Neutrino

Question 7

Define Lepton:

Answer 7

From Light Particle - cannot be split - electron etc

Question 8

Define Quark:

Answer 8

Small Particles - Protons and Neutrons made of these

Question 9

Define Hadron:

Answer 9

From Heavy Particle - Particles mad of quarks

Question 10

Define Baryon:

Answer 10

3 quarks - proton…..

Question 11

Define Meson:

Answer 11

2 Quarks, Quark and anti quark pair.

Question 12

What do charged particles experience in an electric field?

Answer 12

a Force

Question 13

What direction must all charges move in?

Answer 13

Negative to positive. (Electron Flow)

Question 14

Draw the electric field pattern for a point source - negative

Answer 14

Arrows going inward, toward negative point charge

Question 15

Draw the electric field pattern for a point source - positive

Answer 15

Arrows going outward from the point charge

Question 16

Draw the electric field pattern for 2 point opposite sources

Answer 16

Arrows going from positive to negative point charge

Question 17

Draw the electric field pattern for 2 parallel plates - 1 positive + 1 Negative)

Answer 17

Arrows going from positive to negative plate

Question 18

Define Voltage in relation to Work Done

Answer 18

There is a P.D,. Of 1V between 2 points if 1J of energy is required to move 1C of charge.

Question 19

What equation relates the velocity of an electron to its charge and the potential difference across a point?

Answer 19

QV=1/2mv^2

Question 20

Define - Potential Difference

Answer 20

work done moving unit charge between 2 points

Question 21

What does a moving charge produce?

Answer 21

a magnetic field

Question 22

What can we use to visualise the magnetic field around a wire

Answer 22

left hand grip rules

Question 23

What can we use to relate the directions of Force, Field and Current

Answer 23

Secret sign of the Physicist

Question 24

What equation relates mass lost in a nuclear reaction to it’s energy?

Answer 24

E=mc^2

Question 25

What is the atomic number?

Answer 25

No. Protons

Question 26

What is the mass number?

Answer 26

No. Nucleons (particles)

Question 27

Define: Decay

Answer 27

the spontaneous and random process by which unstable atomic nuclei transform to become more stable by emitting radiation

Question 28

What is an alpha particle?

Answer 28

Helium Nucleus

Question 29

What is a Beta Particle?

Answer 29

Fast Electron

Question 30

what should we not round mass during nuclear equations?

Answer 30

It's soooooo soooooo small.

Question 31

Define Fission

Answer 31

Nucleus is split, Energy is released.

Question 32

Define Fusion

Answer 32

Multiple Nuclei fuse together, mass is lost, Energy Released.

Question 33

What is Snell's Law?

Answer 33

n=sinθ1/sinθ2

Question 34

What does the refractive index of an object tell us?

Answer 34

Ratio of c to Speed of light in that material. Tells us how much light will refract entering that material.

Question 35

How can we measure the refractive index of a medium?

Answer 35

Snell's Law experiment.

Question 36

What is the equation linking critical angle to total internal reflection

Answer 36

n=1/sinθc

Question 37

what is the critical angle of a material

Answer 37

then angle where Refraction converts to TIR

Question 38

which colour of light refracts the most?

Answer 38

Violet

Question 39

why don’t all colours of light refract the same in a material

Answer 39

n depends on frequency

Question 40

what property of a wave remains constant in any transparent material?

Answer 40

frequency

Question 41

what is an application of Total Internal Reflection?

Answer 41

Fibreoptics

Question 42

What is Irradiance?

Answer 42

I at a surface on which radiation is incident is the𝐸𝐸e power per unit area.

Question 43

what are the units of Irradiance?

Answer 43

watts per square meter

Question 44

What is the Irradiance equation?

Answer 44

I = P/A

Question 45

what is the invers square law of light

Answer 45

Id2 =Id2 , d increases by a factor of 2 the Irradiance decreases by a factor of 4

Question 46

How can we prove the Invers Square Law of light?

Answer 46

Description of experiment. Vary distance and measure Light Level.

Question 47

What are the 2 types of interference?

Answer 47

Constructive and Destructive

Question 48

Define Path difference

Answer 48

the difference in the length of the path from 2 sources to a set point

Question 49

why do waves experience constructive interference

Answer 49

the waves meet exactly in phase

Question 50

why do waves experience destructive interference

Answer 50

the waves meet exactly out of phase

Question 51

what is the equation for constructive interference?

Answer 51

Path difference = mλ

Question 52

what is the equation for Destructive interference?

Answer 52

Path difference = (m+1/2)λ

Question 53

what is the equation for diffraction gratings?

Answer 53

d sinθ =mλ

Question 54

Describe the Bohr model of the atom

Answer 54

Nucleus made of protons and neutrons with orbiting electrons

Question 55

what is the ground state

Answer 55

the lowest energy level of an electron in the atom

Question 56

when is a photon emitted?

Answer 56

when an electron moves down the energy levels

Question 57

what must happen for an electron to move up the energy levels

Answer 57

it must receive energy

Question 58

what does the word quantized refer to in spectra

Answer 58

the discrete energy levels - nothing can be in the middle

Question 59

what equation links energy transition in an atom to a photons wavelength

Answer 59

E2-E1=hc/lambda

Question 60

how can an electron be exited?

Answer 60

collisions with free electrons or absorption of photons

Question 61

what are Fraunhofer lines

Answer 61

dark lines in emission spectra from sun

Question 62

what does laser stand for

Answer 62

light amplification by stimulated emission of eradiation

Question 63

What is the evidence for the wave Model of light?

Answer 63

Diffraction, Refraction. Reflection, Interference and Polarization

Question 64

What is the evidence for the Particle Model of light?

Answer 64

Line Spectra, Band Spectra, Mathematics, Photoelectric Effect, Reflection and Refraction

Question 65

what is the 1st assumption of the Quantum Theory of light?

Answer 65

light is a stream of tiny, individual "wave packets" called Quanta or Photons.

Question 66

What is the velocity of a photon in air?

Answer 66

c (3*10^8m/s)

Question 67

what does the energy of a photon depend on?

Answer 67

Frequency

Question 68

What equation can we use to calculate the Energy of a photon?

Answer 68

E=hf

Question 69

Describe an experiment to demonstrate the photo electric effect

Answer 69

UV light, shone on a zinc plate, attached to a -ve charged electroscope

Question 70

why is the photoelectric effect not proof for the wave model of light?

Answer 70

changing brightness does nothing.

Question 71

What is the work function of a metal?

Answer 71

Minimum Energy which must be supplied to enable an Electron to escape from the surface.

Question 72

A photon of energy less than the work function incident om a metal. What will happen?

Answer 72

Nothing

Question 73

A photon of energy = the work function incident om a metal. What will happen?

Answer 73

An electron will just be emitted

Question 74

A photon of energy more than the work function incident om a metal. What will happen?

Answer 74

the extra energy will be converted to Ek of the electron

Question 75

What is the threshold frequency of a metal?

Answer 75

minimum frequency that the Photon must be to eject an electron

Question 76

what is the equation for threshold frequency?

Answer 76

Ek = hf - hf0

Question 77

On a graph of Ek vs F. What represents the threshold frequency?

Answer 77

x intercept