Particles Flashcards
What is the mass (kg) of a proton or neutron?
1.67x10⁻²⁷
What is the Charge (C) of a proton and electron?
Proton: +1.6x10⁻¹⁹
Electron: -1.6x10⁻¹⁹
What is specific charge?
Specific charge is the charge per unit of mass of a particle.
How do you calculate specific charge?
specific charge(Ckg⁻¹) = Charge(C) / Mass(kg)
What happens to the Wavespeed, Wavelength and Energy of EM waves as their frequency increases?
Wavespeed stays the same.
Wavelength decreases.
Energy increases.
Name all parts of the EM spectrum from low-high frequency.
Radiowaves.
Microwaves.
Infrared.
Visible Light.
Ultraviolet.
X-ray.
Gamma.
What symbol is used to represent the speed of light?
c
What symbol is used to represent Planck’s Constant?
h
What are photons?
Small packets of energy formed by quantising light.
How do you calculate the energy of a photon?
E = hf
Or
E = hc / λ
What is minimal energy?
Minimal energy is used instead of mass to describe quantum particles.
How do you calculate the minimum energy of a particle?
E = mc²
What equation links Energy(E), Charge(Q) and Voltage(V)?
E = QV
Energy = Charge x Voltage
Why can’t anything travel faster than light?
As particles approach “c” they gain mass. At “c” the mass becomes infinite. It is impossible to accelerate beyond light as an infinite force would be needed.
What is minimum energy measured in?
Electron volts (eV)
How many Joules (J) in one electron volt?
1.6x10⁻¹⁹J
Same as the charge of an electron or proton.
What is the strong force?
A short range force that works on quarks. It keeps the nucleus stable.
What is the equation for Beta minus decay?
Neutron —> proton + electron + antineutrino
What is the equation for Beta plus decay?
Proton —> neutron + positron + neutrino
What are the characteristics of antimatter?
For every particle there is a corresponding antiparticle.
Antiparticles have the same mass but opposite properties.
What happens when a particle and antiparticle collide?
ANNIHILATION
Why are two photons propelled in opposite directions when annihilation occurs?
Because both momentum and energy must be conserved.
What is pair production?
When high energy photons produce a particle and antiparticle. (The particles are propelled in opposite directions)
List the fundamental forces from strongest-weakest.
Strong Force, Electromagnetic Force, Weak Force, Gravity
List the fundamental forces from longest-shortest range.
Electromagnetic and Gravity, Strong force, Weak force
What is the range of the strong force?
3fm
What is the range of the weak force?
0.001fm
What is the range of the Electromagnetic force?
Infinite
What is the range of the Gravitational force?
Infinite
What is the relative strength of the strong force?
1
What is the relative strength of the weak force?
1x10⁻⁶
What is the relative strength of the Electromagnetic force?
1x10⁻²
What is the relative strength of the gravitational force?
1x10⁻³⁸
What are the exchange particles of the strong force?
Gluons (g) and pions (π)
What is the exchange particle of the weak force?
W and Z boson (W⁺, W⁻, Z⁰)
What is the exchange particle of the Electromagnetic force?
Virtual photon (γ)
What is the exchange particle of the gravitational force?
Graviton
Why does the weak force have such a short range?
W bosons are very large and have a larger mass which results in a shorter range.
What determines the range of a fundamental force?
The mass of its exchange particle.
Why does the Electromagnetic force have an infinite range?
Photons have a mass of 0 and since range is determined by mass the range is infinite.
Why does the strong force have a short range?
Gluons interact with each-other.
What are the two types of lepton?
Electron and neutrino