Higher Physics: Unit 2 - Particle and Waves

Tera

x10^12

Giga

x10^9

Mega

x10^6

kilo

x10^3

Milli

x10^-3

Micro

x10^-6

Nano

x10^-9

pico

x10^-12

Alpha radiation

Particles made of a helium nucleus

Beta radiation

Fast moving electrons

Gamma radiation

high energy electromagnetic radiation

direction of electric field

Same as the direction a positive charge would travel

electric field

a field of force surrounding a charged particle

Electric field equation

Ew=QV=1/2mv^2

Right hand rule: thumb

Thrust

Right hand rule: first finger

Electric field direction

Right hand rule: middle finger

Direction of electron

Interference

the interaction between waves that meet

Coherent wave sources

Produce monochromatic light so have 1 frequency/wavelength and are in phase

out of phase waves

Peaks occur at different times

in phase waves

Peaks occur at same time

constructive interference

Occurs when waves add together and waves from the same source arrive in phase

destructive interference

Occurs when waves subtract from each other and waves from the same source arrive half a wavelength out of phase

Path difference equation for maxima

m(lambda)

Path difference equation for minima

(m+1/2)lambda

maxima of a wave

When waves meet in phase and constructive interference occurs

minima of a wave

When waves meet out of phase and destructive interference occurs

Path difference

Extra difference a wave must travel compared to its partner wave

Slit separation equation

dsinØ=m(lambda)

When light enters a denser medium

Wavelength and speed decreases, frequency stays constant

frequency equation

v=f(lambda)

When light enters a less dense medium at

Direction changes

refractive index

Density of a material

Refractive index equation

n=sinØ1/sinØ2

Refractive index equation (extended)

SinØ/sinØ2=(lambda1)/(lambda2)=(speed1)/(speed2)

High frequency waves

Blue, Indigo, Violet

Low frequency waves

Red, orange, yellow

What frequency refract more

Higher frequency

What frequency refract less

Lower frequency

Critical angle equation

SinØc=1/n

total internal reflection

Light hits a material at an angle bigger than the critical angle

What is the photoelectric effect?

the ejection of electrons from a metal plate when light of sufficient frequency falls on it

What is light?

an electromagnetic wave (photon)

What metal plate does the photoelectric effect not work on?

Copper

What metal plate does the photoelectric effect not work on?

Iron

What metal plate does the photoelectric effect not work on?

Lead

What metal plate does the photoelectric effect work on?

Zinc

What metal plate does the photoelectric effect work on?

Sodium

What metal plate does the photoelectric effect work on?

Potassium

If a light has a high frequency...

small wavelength

If a light has a high frequency...

large energy

If a light has a large energy...

small wavelength

If a light has a large energy...

high frequency

If a light has a low frequency...

large wavelength

If a light has a low frequency...

small energy

If a light has a large wavelength...

low frequency

If a light has a large wavelength...

low energy

What is threshold frequency?

minimum energy a photon must have for the photoelectric effect to occur

What is work function?

minimum energy required for the photoelectric effect to occur

How to find the work function

Eo=hfo

How to find the energy of the photon

E=hf

How to find kinetic energy of an electron

Ek=E-Eo

How to find kinetic energy of an electron

Ek=hf-hfo

What is current when threshold frequency is achieved?

0

What effect does irradiance have on the velocity of an electron?

None

What effect does irradiance have on the energy of a photon?

None

What effect does increasing the irradiance have on current?

Increased current

What effect does decreasing irradiance have on current?

Decreased current

What apparatus is used for the irradiance experiment?

12V power supply, 12V lamp, light detector, light meter and a meter stick

What is a point source?

a source of light that radiates light outwards in all directions

How to find the irradiance

I=P/A

How to find the irradiance

I=Nhf

What is irradiance?

power per unit area

What is the inverse square law?

Id^2=I2d2^2

How to find the irradiance

I=k/d^2

Why is a laser not a point source?

Light is focused in a singular beam so photons travel in a concentrated beam and maintain their irradiance

How many fundamental particles are there?

12

What are fermions?

Matter particles

What are the types of fermions?

quarks and leptons

Example of a quark

Up (u)

Example of a quark

Down (d)

Example of a quark

Charm (u)

Example of a quark

Strange (s)

Example of a quark

Top (t)

Example of a quark

Bottom (b)

Example of a lepton

electron (e)

Example of a lepton

electron neutrino

Example of a lepton

tau (fancy T)

Example of a lepton

tau neutrino

Example of a lepton

muon (fancy m)

Example of a lepton

muon neutrino

What is anti-matter

particles that have the same mass as their matter twins, but with an opposite charge, magnetic characteristics, and other properties

What charge does an up quark have?

+2/3

What charge does a charm quark have?

+2/3

What charge does a top quark have?

+2/3

What charge does a down quark have?

-1/3

What charge does a strange quark have?

-1/3

What charge does a bottom quark have?

-1/3

What charge does a lepton have?

-1

What charge does a lepton neutrino have?

0 (No charge)