Module 5: Newtonian World and Astrophysics Flashcards
What are energy levels?
The name of the discrete set of energies that electrons of atoms in a gas can exist in
Why are the energy level of gaseous atoms negative?
Energy is required to remove an electron.
What does if mean is an electron has an energy of zero?
It’s free from the atom.
What is the ground state (Energy levels)?
Most negative energy level.
What does it mean when an electron has been “excited”?
It has moved from a lower energy level to a higher energy level.
What happens if a photon doesn’t have enough energy to free an electron?
If it has just enough energy to move it up an energy level, it excites the electron. This energy is the difference in energy between the two energy levels.
What happens once electrons have been excited?
They go back down to the lowest energy level they can and emit a photon, and when this light is diffracted, you get an emission line spectrum.
What is a spectrum?
A graph of intensity vs frequency.
What is a line spectrum?
A series of lines against a background formed by the diffraction of light emitted from excited electrons.
What are the three types of spectra?
Continuous spectra: The diffraction of white light produces this spectrum.
Emission line spectra: The result of the diffraction of photons emitted when electrons move to lower energy levels, the colourful lines indicate different energies and are against a dark background.
Absorption line spectra: Similar to emission line spectra but there are dark lines against a continuous spectra.
What are the similarities and differences between emission and absorption line spectra?
Similarity: Lines appear at the same frequencies / positions
Difference: Emission is coloured lines against a dark background, while absorption is dark lines against a coloured background
What is required for an object to undergo uniform circular motion?
There must be a resultant force of constant magnitude that is always directed radially inward. This force is called the centripetal force.
Why is speed constant during uniform circular motion?
Resultant force and motion are perpendicular, so no work is done in the direction of motion.
Name some examples of sources of centripetal forces.
- Friction
- Tension
- Gravitational force
- Changes in normal contact force
Define simple harmonic motion.
When a system oscillates about its equilibrium position in a periodic manner.
