astrophysics and cosomology

• What happens to gravitational potential energy during star formation?

  It decreases while kinetic energy increases
• At what temperature does hydrogen nuclei fuse into helium?

  10 million kelvin
• What occurs when radiation pressure equals gravitational force?

  A star is born
• What does a star similar to the sun become after exhausting its fuel?

  Red giant
• What is a planetary nebula?

  Remaining matter from a red giant's death
• What happens to larger stars when they run out of hydrogen fuel?

  They turn into super red giants
• What is the outcome of a super red giant when it exhausts its fuel?

  Gigantic supernova explosion
• What determines whether a star becomes a neutron star or a black hole?

  The initial mass of the star
• What does the Hertzsprung-Russell diagram categorize?

  All types of stars
• What is plotted on the y-axis of the Hertzsprung-Russell diagram?

  Luminosity of the star
• How does temperature change on the Hertzsprung-Russell diagram?

  Increases to the left
• Where do white dwarfs appear on the Hertzsprung-Russell diagram?

  Lower left-hand region
• What is the Chandrasekhar limit?

  Maximum mass of a white dwarf star
• What is the value of the Chandrasekhar limit?

  1.4 solar masses
• What happens if the Chandrasekhar limit is exceeded?

  A neutron star is formed
• What can electrons in an atom do regarding energy levels?

  Occupy specific allowed energy levels
• What is the ground state of an electron?

  Most negative energy state
• What happens when an electron is ionized?

  It escapes the atom
• Why do energy levels have negative values?

  Energy must be inputted to remove electrons
• What is the conversion factor from electron volts to joules?

  1.6 times 10 to the power of -19
• What does the energy of a photon equal?

  hf
• How do you calculate the frequency of a photon absorbed?

  Frequency = change of energy / Planck's constant
• What is Planck's constant?

  6.63 times 10 to the power of -34
• What is the wavelength of a photon emitted during a transition?

  Wavelength = hc / change of energy
• What causes an emission spectrum?

  Hot gas emits photons at specific wavelengths
• How does an absorption spectrum appear?

  Dark lines on a continuous spectrum background
• What is diffraction?

  Spreading of light through a gap
• What is a diffraction grating?

  A surface with multiple slits for light
• What does the equation d sin(θ) = nλ represent?

  Diffraction pattern of light through slits
• What does 'd' represent in the diffraction equation?

  Spacing between individual lines
• How is 'θ' defined in the diffraction equation?

  Angle corresponding to the order of diffraction
• What is the significance of 'n' in the diffraction equation?

  Order of the diffraction pattern
• What is the purpose of a diffraction grating?

  To analyze incoming light
• What does diffraction refer to?

  Spreading of light through a gap
• What does a diffraction grating consist of?

  Multiple slits along its surface
• What happens to light when it passes through a diffraction grating?

  It spreads, creating a diffraction pattern
• What is the equation governing diffraction?

  d sin(theta) = n lambda
• If a diffraction grating has 300 lines per millimeter, what is 'd' in meters?

  $1/300 \times 10^3 \text{ m}$
• What is the angle theta in the context of diffraction?

  Angle corresponding to the order of diffraction
• How is the angle theta related to the position of a fringe?

  It corresponds to the position of the fringe