ASTR 5

Describe two ways an atom can become excited

Collisions, absorption of a photon

Why do hot stars look bluer than cool stars?

The wavelength that a star radiates the most energy is inversely proportional to the temperature.

What kind of spectrum does a neon sign produce?

An emission spectrum

How can the Doppler effect explain wavelength shifts in both light and sound?

The Doppler effect is produced when the source and observer of a wave are moving relative to each other, regardless of the type of waves produced

Which of the following statements about the nucleus of a typical atom (such as a carbon atom in your little finger) is FALSE?

the nucleus repels the electrons which move around it

Where in an atom would you expect to find electrons?

in an orbit around the nucleus

Where in an atom would you expect to find protons?

within the nucleus

Where in an atom would you expect to find neutrons?

Within the nucleus

Explain how we can deduce the temperature of a star by determining its color

The peak wavelength of a blackbody spectrum, which is the color, is inversely proportional to its temperature.

An astronomer discovers a new star and wants to measure its temperature. She would typically do this by _____.

making a blackbody curve and finding the wavelength of the peak (maximum)

Wien's Law relates the wavelength at which a star gives off the greatest amount of energy to the star's _____.

temperature

Why is an absorption spectrum especially useful for astronomers?

It has dark lines in it that allow astronomers to determine what elements are in the star

An artist who likes working with sources of light decides to make a modern sculpture out of electrified glass tubes that contain very thin (rarified) neon gas. When the sculpture is finished, and the electricity is turned on, the tubes glow with a rich red color. What we are seeing is _____.

an emission spectrum

Astronomers observe a typical star using a telescope and a spectrometer. They will see _____.

more than one of the above

Atoms typically consist of electrons, protons, and neutrons. The most common isotope of one element, however, only has two of these three types of particles. This element is _____.

hydrogen

Two versions of an element with different numbers of neutrons are called _____.

isotopes

When an atom has lost one or more electrons, it is said to be _____.

ionized

To go from a lower level in an atom to a higher level, an electron must _____.

absorb a photon of energy

The ground state in an atom is _____.

the electron orbit with the lowest possible amount of energy