Astr 121 (the sun)

at the end of the p-p chain of nuclear fusion in the sun, hydrogen nuclei have been converted not:

a helium nucleus

according to the formula e=mc2:

a little bit of mass can be converted into a substantial amount of energy

what will take the shortest time to emerge form the suns's photosphere?

a photon of gamma rays

when these particles spiral down along the magnetic field into the atmosphere, they are responsible for:

aurorae

the hotter region directly above the sun's visible surface is called the:

chromosphere

when great currents of hot material rise inside the sun, energy is being transferred by a process known as:

convection

the hottest zone in the sun is the:

core

which part of the sun's atmosphere has the lowest density?

corona

which part of the sun's atmosphere is the hottest?

corona

what particle has the lowest mass?

electron

what is solar wind mostly made of?

electrons and protons

when a positron and an electron collide, they will produce:

energy in the form of a gamma ray

the granulation pattern that astronomers have observed on the surface of the sun tells us that:

hot material must be rising from the sun's hotter interior

the most common element in the sun is:

hydrogen

as astronomers have learned more about the structure of the sun, they have found that it:

is made entirely of hot gas

what happens to the positron created during the p-p chain of nuclear reactions inside the sun?

it quickly collides with an electron and turns into gamma-ray energy

astronomers now realize that active regions on the sun are connected with:

loops of magnetic field emerging from the surface of the sun

the source of energy for the sun is a process called:

nuclear fusion

why is our sun not collapsing?

nuclear fusion in the core keeps the temperature and the pressure inside the sun at a high enough level so that gravity is balanced

where in the sun does fusion of hydrogen occur?

only in the core

the part of the sun that you can see directly is called its:

photosphere

bright "clouds" in the chromosphere right around the location of sunspots are:

plages

the material inside the sun is in the form of a:

plasma

the antimatter version of an electron is called a:

positron

when energy is first produced by fusion deep in the core of the star, that energy moves outward mostly by what process?

radiation

when two light element collide to undergo nuclear fusion:

some of the energy in their mass is released

the sun's chromosphere contains many jet-like projections that stick up into the transition region. these spikes of gas are called:

spicules

which of the following is a way for astronomers to learn more about the interior of the sun

study the corona during eclipses of the sun

which part of the sun has the greatest density?

the core

as you go upwards from the sun's photosphere:

the density (number of atoms in a unit volume) decreases

the sun's photosphere is:

the part of the sun from which the light comes that we see when we look at the sun with our eyes

which mechanisms do astronomers believe is responsible for making the sun's outer atmosphere so much hooter than its photosphere?

the sun's magnetic field interacting with the charged particles that make up the atmosphere

how do astronomers know how strong the magnetic field of the sun is?

they measure the zeeman effect (the splitting of spectral lines)