Topic 5

Photons get more energy so electrons have a higher maximum kinetic energy when struck by the the photons

More photons striking the metal surface so more electrons emmitted per second.

Evidence of an experiment thats been performed and is repeatable.

E (Max Kinetic) = E (Photon) - Φ (Work Function)

E (Photon) = h (Planck’s Constant) * f (Frequency) OR hc (Planck’s Constant * Speed of Light) / λ (Wavelength)

F (Threshold) = Φ (Work Function) / h (Planck’s Constant)

Joules —> EV, Divide

Atoms absorb photons with different wavelengths and corresponding discrete energy levels. Each wavelength represents an energy level and a colour. If all the colours from each energy level / wavelength were projected, there would be the absorbtion spectrum. The missing colours are the wavelengths / energy levels absorbed by the atoms. Set of frequencies absorbed depends on the element.

Atoms emit photons with discrete wavelengths and corresponding discrete energy levels. Each wavelength represents and energy level and a colour. If all the colours from each energy level / wavelength were projected, there would be the emmissioh spectrum. The coloured lines are the photons with discrete wavelengths / energy levels emmitted by the atoms.

In a fluorescent tube, current is passed through a tube of mercury gas. The electrons colllide with the electrons of the vapour which excites them to a higher energy level ( glow in the dark). The electrons then falls to a lower more stable energy level and release a photon with the same energy the electron lost (stops glowing).

Absorbs high energy UV photons emitted by the vapour which is dangerous to humans and gives out visible light

Removing an electron from an atom

Leads to a diffraction pattern which could imply electrons behave as waves. As the volatage increases, kinetic energy increases so wavelength get shorter as λ = hc/e. Graphite structure has small gaps in it similar to λ. nλ = dsinθ so smaller λ means smaller angular seperation. De Broglies equation proves that as λ gets smaller, momentum increases.

Light where oscillations are in a single direction, perpendicular to direction of propagation