Wave Particle Duality

Question 1

Electrons

Answer 1

Fundamental Particles
Rest mass and Fixed Charge in the data book

Question 2

Electron Particle Behaviour

Answer 2

Gain Kinetic Energy
Deflected by electric of magnetic fields

Question 3

Electron Wave Beahaviour

Answer 3

De Broglie - Wavelength based on momentum
λ = h/p = h/mv
λ: De Broglie wavelength in metres
h: Planck’s constant in the data book
p: Momentum (Mass x Velocity)

Question 4

Kinetic Energy Equation to Memorise

Answer 4

KE = 0.5mv^2

Question 5

Electron Diffraction

Answer 5

Shows wave properties of electrons
Electron gun
Hot wire releases electrons by thermionic emission
Electrons pass through an accelerating P.D. (+ve anode)
Electrons pass through a thin sheet of polycrystalline graphite
Electrons diffract and strike screen, producing an interference pattern
Vacuum
Pass through hole as a beam with high momentum
λ =(approx) 1 x 10^-10m
If the P.D. increases, λ decreases, less diffraction so rings have a smaller diameter

Question 6

Electron Volt (eV)

Answer 6

1 eV is energy gained by 1 electron, travelling through a potential difference of 1 Volt
1 eV = 1.6 x 10^-19
Can be used for protons as they have the same charge

Question 7

Electron Volt Conversion

Answer 7

W = VQ
Work Done / J : W
Voltage / V : V
Charge / C : Q

Question 8

Change in Potential Difference

Answer 8

As V increases, electrons gain more EK and speed
Momentum increases so wavelength decreases
KE = 0.5mv^2 -> If KE x2 then v x √2

Question 9

Large Masses

Answer 9

For Large Masses, the momentum is much larger so λ decreases
This makes it difficult to observe wave behaviour
λ rarely equals gap size for an object