Astronomy Test 1 Part 5

The first person (to the best of our knowledge) regularly to turn a telescope to astronomical observations was _______.

Galileo Galilei

The idea that atoms radiate energy only when their electrons move from higher to lower energy levels was first advanced by ______.

Niels Bohr

What happens as an electron falls from a higher level to a lower level in an atom?

a photon is given off

The size of the device that gathers (collects) radiation is called a telescope's _____.

aperture

Why do different types of atoms (elements) give off or absorb different spectral lines?

because the spacing of the energy levels is different in different atoms

The most important function of an astronomical telescope is to ______.

collect as much light as possible and bring it to focus

A new technique called adaptive optics allows astronomers to ______.

compensate for changes in Earth's atmosphere and achieve better resolution

One of the great triumphs of spectroscopy was when astronomers identified a new element in the Sun (one that was only later found on Earth). Today, this element is called ______.

helium

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

You are alone in a large, completely dark auditorium on Earth. What kind of telescope should I use from the other side of the auditorium to detect the electromagnetic radiation emitted by your body?

infra-red

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

ionized

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

isotopes

How do astronomers learn what elements are present in a given star?

look at the absorption lines in its spectrum

Which of the following is NOT done best with a spectrometer?

measuring how bright sources of light in the universe appear

The largest visible-light telescopes in the world use what device to collect as much light as possible before the light is brought to a focus (to act as the light bucket)?

mirror

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

more than one of the above

To get away from the pressures of your astronomy class you and some friends decide to go to a football game. In the stadium, a friend gives you her binoculars to look through, and suddenly you realize that you are back to a subject covered in astronomy class. What type of telescope are you looking through when you use binoculars?

refracting

The earliest type of telescopes used by astronomers were _____.

refractors

The two regions of the electromagnetic spectrum where the Earth's atmosphere is transparent (radiation can get in) are visible light and _____.

some radio waves

Which of the following consists of electro-magnetic waves with the shortest wavelength?

the waves of a dental x-ray