Quantum Flashcards
Electron diffraction
Bending and spreading of e when passing through narrow slit or obstacle, showing wave-like properties
Photon
Discrete packet of EM energy.
Shows particle-like and wave-like properties
Photoelectric effect
Emission of electrons from metal surface when em wave with high enough frequency incident
Wave-Particle Duality
Particles exhibit wave and particle like properties. Evident by photoelectric effect (particle) and e diffraction (wave)
KE, Current and Freq, Intens
Freq increase, KE increase, Current same
Intens increase, Current increase, KE same
Gold leaf electroscope set up
Zinc plate attached to gold leaf which initially has negative charge
Gold leaf repelled by negatively charged rod
Place UV closer to metal plate
Observation and explanation
Gold leaf falls more quickly
Increases intensity incident on metal
Increases number of e emitted per second
So loses neg charge more quickly
Higher freq light source
Doesn’t change how quick gold leaf falls
Max EK of e increase with f
Energy and intensity independent
Intensity affects how quickly it falls not f
Why does Emission of photo electron happens as soon as radiation is incident on metal surface
Single photon interacts with single e
If energy of photon equal to work function, e released instantly
Using positively charged plate
No change in gold leaf’s position
Excess +charge on surface
Any e emitted will be attracted back
How to work out number of photons
Power / Energy
As energy Increases, number of photons decrease
