Astronomy Test 2 Study Guide

The sun’s surface seethes and churns with a bubbling pattern. Why?We are seeing hot gas rising and cool gas falling due to the convection that occurs beneath the surface
Which of the following statements about electrons is false?Electrons orbit the nucleus rather like planets orbiting the sun
Without telescopes or other aid, we can look up and see the moon in the night sky because it?Reflects visible light
If you heat a gas so hot that collisions are continually bumping electrons to higher energy levels, when the electrons fall back to lower energy levels the gas produces?An emission line spectrum
Sunspots are cooler than the surrounding gas in the photosphere because?Strong magnetic fields slow convection and prevent hot plasma from entering the region
Which of the following correctly describes how the process of gravitational contraction can make a star hot?When a star contracts in size, gravitational potential energy is converted to thermal energy
How can we measure the strength of magnetic fields on the Sun?By looking for the splitting of spectral line in the Sun’s spectrum
Why is the Earth’s daytime sky blue?Molecules scatter blue light more than red light
To calculate the masses of stars in a binary system, we must measure their?Orbital period and average orbital distance
Why do flat disks form around young stars?Collisions between rotating gas particlese flatten the gas cloud along the axis of rotation
What is a planetary nebula?Gas ejected from a low mass star in its final stage of its life
What keeps the Sun’s outer layers from continuing to fall inward in a gravitational collapse?Outward pressure due to super heated gas
All stars are born with the same basic composition, yet stars can look quite different from one another. Which two factors primarily determine the characteristics of a star?Its mass and its stage of life
Which of the following properties cannot be determined from a spectrum of a star?Speed perpendicular to my line of sight
To determine a stars surface temperature, you need to measure?Its color
Which of the following is not a way light and matter interact?Evaporation
By what process does the sun generate energy?Nuclear fusion
If a distant galaxy has a substantial red shift, then everyone living in that galaxy would see a substantial red shift in a spectrum of our galaxy.Yes, and the red shifts would be the same.
Since all stars begin their lives with the same basic composition, what characteristic most determines how with they will differ?Mass with which they are formed
What can we learn about a star from a life track on a HR diagram?What surface temperature and luminosity it will have at each stage of its life
When an electron in an atom goes from a higher energy state to a lower energy state, the atom?Emits a photon of a specific frequency
In binary stars, the orbital period depends on the masses of the stars and the sizes of the orbits. Why is this so valuable to know?This is the main way we determine the masses of the stars
Which of the following statements about the sun spot cycle is not true?The rate of nuclear fusion in the sun peaks about every 11 years
A star’s luminosity is the?Total amount of energy that the star radiates each second
Which of the following best describes why we say the at light is an electromagnetic wave?The passage of a light wave can cause electrically charged particles to move up and down
If the sun’s surface became much hotter(while the sun’s size remained the same), the sun would emit more ultraviolet light but less visible than it currently emits.No, the suns warmer surface would emit more light at all wavelengths
If star A is closer to the sun than star B, than star A’s parallax angle is?Larger than that of star B
Why does the sun shine (clicker)?nuclear fusion
What is a hydrogen nucleus made of (clicker)?a proton
What is a helium nucleus made of (clicker)?One neutron and one proton
One proton and two neutrons
Three protons and no neutrons
Three protons and two neutrons


What would happen inside the Sun if a slight rise in core temperature led to a rapid rise in fusion energy (clicker)?The core would expand and cool
Why are very high temperatures required for nuclear fusion to occur (clicker)?The two protons have + charges and repel. Only at high speed can they collide close enough for nuclear forces to bind them
Formula for de Broglie wavelength (clicker)?λ = h/mv
Which of the following can be used to measure the mass of the Sun? (clicker)Venus-Sun distance and the length of Venus’ “year”.
What causes solar activity? (clicker)—The stretching and twisting of magnetic field lines near the Sun’s surface causes solar activity.
—Bursts of charged particles from the Sun can disrupt communications, satellites, and electrical power generation
How does solar activity vary with time?Activity” rises and falls in 11-year cycles