Chapter 5.4 and 5.5 Flashcards Preview

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Flashcards in Chapter 5.4 and 5.5 Deck (23)
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1
Q

Thermal Equilibrium

A

When heating is balanced by cooling.

2
Q

Temperature

A

A measure of how energetically the atoms that make up an object are moving about.

3
Q

Thermal Motions

A

The random motion of atoms and molecules that create temperature.

4
Q

Absolute Zero

A

The temperature at which all thermal motions stop.

5
Q

Kelvin Temperature Scale.

A

Starts with absolute 0 at 0. Same degrees at Celsius add 273.15. So water freezes at 27.15 and boils at 373.15K

6
Q

Why is Kelvin useful?

A

When temperature is measured in kelvin, the energy of the particles is proportional to the measured temperature. So, 200k is twice as energetic as 100k.

7
Q

Luminosity

A

The total amount of light leaving a source. Measured in watts.

8
Q

Luminosity

A

The total amount of light leaving a source. Measured in watts.

9
Q

Blackbodies

A

Objects that emit electromagnetic radiation only because of their temperature, not their composition. Emit just as much radiation as their absorb through their surroundings

10
Q

Blackbody Spectra

A

The spectrum of electromagnetic energy emitted by a blackbody per unit of area per second.

11
Q

Stean Boltzmann Law

A

The increase of the luminosity of a blackbody is proportional to the fourth power of the temperature. F=ot^5

12
Q

Flux

A

Amount of energy radiated by each square meter of the surface of an object each second.

13
Q

Luminosity= (flux) * _____

A

Surface area of the object.

14
Q

F=oT^4

A

Stefan Bolzman law. Flux is equal to sigma times the temperature to the fourth power.

15
Q

If the temperature of an object doubles what happens to the amount of energy being released?

A

It goes up by 2^4 or 16 times the original energy.

16
Q

Wien’s Law

A

The wavelength of the spectrum is inversely related to th temperature of the object. If you double the temperature, the peak wavelength becomes half of what it was. T= b/peak wavelength

17
Q

Stefan Boltzmann Constant

A

5.67 times 10^08 watts/m2k^4

18
Q

Brightness

A

The amount of light arriving at a particular location.

19
Q

Brightness vs Luminsoity

A

Brightness depends on distance because it measure slight arriving at a location. Luminosity is independent because it measures light leaving an object.

20
Q

How does brightness depend of distance.

A

Is is inversely proportional to the square of the distance between the source and the object.

21
Q

Brightness=

A

Luminsoity/4pied^d2

22
Q

Albedo

A

Fraction of light that reflects from a planets surface

23
Q

A planet covered in snow would have close to a ___ albedo. A planed covered in black rocks would have close to ___ albedo

A

1, 0