P7.4 pt 1 Flashcards
- What is an example of a hot object that emits a continuous range of electromagnetic radiation?
-stars
- What so all hot objects (including stars) emit?
-a continuous range of electromagnetic radiation, whose luminosity and peak frequency increases with temperature
- What is a continuous spectrum?
-a spectrum without gaps
- What is the peak frequency in a continuous spectra?
-the wavelength that is emitted most
- What does the peak frequency emitted by an object depend on?
-higher temperature= higher energy photons= higher peak frequency
- What does luminosity or brightness depend on?
-temperature
- How can we tell how hot a star is by its colour?
- red= low frequency= cool
- blue= high frequency= hot
- What is ionisation?
-the removal of electrons from atoms to make ions WHEN THE ELECTRON GAINS ENOUGH ENERGY
- What is the structure of an atom?
-tiny positive nucleus surrounded by shells/energy levels of negative electrons
- What is an energy level?
-a shell
- Where are the lowest energy levels?
-nearest the nucleus
- Why do electrons move between energy levels?
-if they gain or lose energy
- What causes absorption spectrums?
- high temp= electrons jump to higher energy levels (electrons absorb certain frequencies of radiation)
- the frequencies absorbed show as dark lines (on a continuous spectra)
- What causes emission spectrums?
-electrons unstable in high energy levels
=fall to lower levels
=lose energy by emitting particular frequency= series of bright lines of emitted frequencies (on a black background)
- What is the relationship between wavelength and energy?
- inversely proportional
- smaller wavelength= higher energy
- What do specific spectral lines in the spectrum of a star provide evidence of? How?
- the chemical elements present in it
- compare line spectra’s to known line spectra’s
- What part of a star emits a continuous spectrum of radiation?
-the photosphere (surface)
- What is the relationship between the volume of a gas and its pressure at a constant temperature?
- inversely proportional
- larger volume= less pressure
- Why is the volume of a gas inversely proportional to its pressure at a constant temperature?
-at larger volume there is less collisions between the particles and the container walls so less pressure is exerted on the walls
- What does the pressure of a gas depend on?
-how fast the molecules are moving and how often they hit the walls of the container they are in
- What is the equation to find pressure?
Pressure x volume= Pressure x volume
- What is the relationship between pressure and absolute temperature?
-directly proportional
- Why may the pressure and volume of a gas vary with temperature?
-increase temperature= faster particles with more energy= hit container walls more wand harder= increase pressure
- What is the equation for pressure and temperature?
p/t=p/t
- What is the relationship between volume and absolute temperature?
-directly proportional
- What is the equation for volume and temperature?
v/t=v/t
- What effect does increasing the temperature have on volume of gas?
- increases
- molecules further apart so less collisions but more kinetic energy so hit with more force
- What two things are proportional to absolute temperature?
- volume
- pressure
- What is the kinetic theory?
-says that gases consist of very small moving particles that collide with each other and walks, most is empty space
- What is absolute 0?
- the littlest kinetic energy atoms can have
- ‘-273⁰C’
- What is the start of the Kelvin scale?
-absolute zero (-273)
