Astronomy And Cosmology Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

Luminosity

A

The total power output of radiation emitted by a star

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Radiant flux intensity

A

The observed amount of intensity, or the radiant power transmitted normally through a surface per unit of area, of radiation measured on Earth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the inverse square law of flux

A

F=L/4pid^2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Define Standard candle

A

An astronomical object that has a known luminosity due to a charecteristic quality possessed by that class of object

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Examples of standard candles

A

1) Cephid variable star
2) type 1a supernova

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How do we measure astronomical distances

A

Using standard candles, we know the luminosity we should measure the radiant flux intensity and calculate the distance using the Inverse square law of flux

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Wien’s displacement law

A

The black body radiation curve for different temperature peaks at a wavelength which is inversely proportional to the temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is wein’s law equation

A

Wavelength max x frequency = 2.9×10^-3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What does a stars luminosity depen on

A

1) it’s radius
2) it’s surface temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Stefan boltzmann law

A

The total energy emitted by a black body per unit area per second is proportional to the 4th power of the absolute temperature of the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Stefan boltzmann equation

A

4pir^2sigmaT^4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the difference in emission spectra in galaxy

A

1) increase in wavelength
2) shifted towards the red end of the spectrum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Doppler effect

A

The apparent change in wavelength or frequency of the radiation from a source due to its relative motion away from or toward the observer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

If the object is moving away from the earth is it redshift or blueshift

A

Redshift

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Redshift

A

The fractional increase in wavelength due to the source and observer receding from each other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Doppler redshift equation

A

^lamda/lamda = ^f/f =v/c

17
Q

What gave evidence for an expanding universe

A

Doppler redshift

18
Q

Hubble’s law

A

The recession speed of galaxies moving away from the earth is proportional to their distance from the earth

19
Q

Hubble’s law equation

A

V=Hod

20
Q

What is big bang theory

A

The universe started from an extremely hot , dense singular point

21
Q

What is the age of the universe

A

To=1/H0