Module 4 Part 2- Waves and Quantum Physics Flashcards
What is the difference between a transverse and a longitudinal wave
Transverse waves oscillate at 90° to the direction of energy transfer whereas longitudinal oscillations are parallel to the direction of energy transfer.
Transverse waves can travel through a vacuum but longitudinal waves need a medium to travel through
Transverse waves have peaks and troughs whereas longitudinal waves have
Compressions and rarefactions
What is amplitude
Amplitude is the distance from the peak/trough to the equilibrium position
What is wavelength
Wavelength is the distance from one peak/trough to the next
Define period of oscillation (time period)
The time a wave takes to complete one full oscillation
Define frequency
The number of wavelengths that pass a given point per second-inverse to time period
What is phase difference and what is it measured in
Phase difference is the difference between the displacements of two particles along a wave
or the displacements of two waves-this is measured in degrees° or radians where a circle is a full oscillation
What is it called when two particles reach their peak at the same time
In phase
What is it called when one particle hits its peak while the other hits its trough
Antiphase
What is reflection
Reflection is when a wave changes direction at the border between two mediums therefore remaining in the original medium-wavelength and frequency remain the same
What is the law of reflection
Angle of incidence=angle of reflection
What is refraction
Refraction is when a wave changes direction towards/away from the normal as it enters a new medium due to a change in speed which occurs when entering a more/less dense medium
What is the photoelectric effect
The photoelectric effect is when photons of electromagnetic radiation are shone onto a metal and photoelectrons are emitted off the surface
What are the conditions that need to be in place for the photoelectric effect to take place
Incident radiations frequency must be above threshold frequency of the metal-f0
What is the name given to the minimum amount of energy to free an electron
Work function-different for each metal
What is the equation that links energy, Planck constant and frequency
Energy = h x f
What happens to the spare energy after the photoelectric effect occurs
A certain amount of energy is used to overcome the work function, the rest is then transferred into to the kinetic energy of the electron
What is the idea of wave-particle duality
It is a theory that de broglie proposed which states that all matter has both wave and particle properties