Astronomy 120 Midterm

Question 1

Formulaic relationship between speed of light, wavelength, frequency?

Answer 1

c = λ f

Question 2

Formulaic relationship between wavelength and light energy?

Answer 2

E = hc / λ

Question 3

Thin plastic is ___ to infrared

Answer 3

transparent

Question 4

What is the “photosphere”?

Answer 4

The visible surface of the sun

Question 5

What is the “chromosphere” and when do we observe it?

Answer 5

The thin hot gas atmosphere above the photosphere, seen during a total solar eclipse

Question 6

What color is the chromosphere and is it cooler or hotter than the photosphere?

Answer 6

Pink, and hotter 🔥

Question 7

Is the sun’s chromosphere a black body?

Answer 7

No

Question 8

What is the pink line in the sun’s chromosphere due to / how is it produced?

Answer 8

Hydrogen. The emission line is produced when collisions excite electrons in Hydrogen and cause them to jump down an energy level.

Question 9

All planets travel around the sun in a ____ plane in a ____ direction.

Answer 9

flat plane, counterclockwise direction

Question 10

Formula with angular momentum, spin and inertia?

Answer 10

L = I w

Question 11

According to the solar nebula hypothesis, as the cloud collapsed to a smaller size, its inertial I would __(increase/decrease)___ and the spin rate w would __(increase/decrease)___.

Answer 11

The inertial I would DECREASE and spin would INCREASE according to the law of conservation of angular momentum.

Question 12

What caused the pancaking?

Answer 12

Material moving in the “pancake” has more acceleration and can’t collapse, but stuff above it has less acceleration and CAN collapse into the pancake.

Question 13

The ____ ensured common revolution direction and spin of all planets (except Venus) and provides a fossil record.

Answer 13

The angular momentum conservation

Question 14

What wavelength of the electromagnetic spectrum is normally used to study newborn planetary systems? Why?

Answer 14

Near-infrared light. It can penetrate the dust surrounding newborn stars that blocks light in the visible spectrum.

Question 15

Outer planets move ___(slower/faster)___ around the sun than inner planets.

Answer 15

Slower

Question 16

Newton’s first law

Answer 16

A body at rest will remain at rest

Question 17

Newton’s second law

Answer 17

The time rate of change is equal to the force imposed on it

Question 18

Newton’s third law

Answer 18

Every action has an equal and opposite reaction