Section 2 Electromagnetic Radiatiob And Quantum Phenomena Flashcards
What is the photoelectric effect
When a metal emits an electron by gaining enough energy via an EV wave
What is threshold frequency
The frequency that the waves must pass to release an electron
What does increasing the frequency of the wave do to electron
An increased kinetic energy
How is the intensity relative to energy
The amount of energy per second hitting an area of metal
What is the number of photoelectrons proportional to
The intensity of the radiation
What happen to the zinc plate when demonstrating the photoelectric effect when it’s negatively charged
The negatively charged metal repels the gold leaf
What happens to the metal when a UV light is shone on it. Which in turn affects the gold leaf. ( Demonstrating the photoelectric effect)
The light causes the metal to lose electrons, which means the gold leaf no longer repels
What is work function
The required energy for an electron to break the bonds holding it there
How many joules are in one electron Volt
1.6 x 10 **-19
What is the name for the lowest energy level an electron can be
The ground state
What is the term when an electron has an energy level higher than the ground state
An excited state
What happens when an electron moves down an energy level
The electron releases a photon with the same energy as the loss of energy as the electron
How do fluorescent tubes emit visible light
They use the excitation of electrons and the photon emissions when they lose energy.
What does the phosphor coating on the inside of the fluorescent tubes do to the photons
It absorbs them and then excites them to much higher energy levels.
What happens after the electron has emitted the main photon
The electrons continue cascading down the energy levels emitting smaller energy level photons
What is a line emission spectra
A series of bright lines on a black background
How can one create a line emission spectra
By shining a fluorescent tube with a prism or diffraction grating ( work by diffracting light of different wavelengths at different angles)
How can one create a line emission spectra
By shining a fluorescent tube with a prism or diffraction grating ( work by diffracting light of different wavelengths at different angles)
What is different about a line emission spectra and line absorption spectra
The black lines on line absorption match to the bright lines in an emission spectra
What are continuous spectras
The spectrum of white light is continuous, if the light is split up from a prism the colours all merge into each other
