2.7 Astronomy

Question 1

Equations for Doppler shift (frequency and wavelength)

Answer 1

f = (velocity of wave/velocity of wave - source ) f0

& = (velocity of wave - velocity of source/velocity of wave ) &0

Question 2

What happens to the magnitude of wavelength observed if the speed of source is the same but direction changes

Answer 2

Same difference only opposite
& = &0 + 0.1
New& = &0 -0.1

Question 3

What is the difference between cosmological red shift and Doppler redshift

Answer 3

CRS is caused by space between observer and source increasing
DRS is caused by object moving away from observer

Question 4

Equation for z parameter (&,f and v)

Answer 4

z = delta &/ &0
z = delta f / f0
z = v of source / c (v of wave)

Question 5

What does delta lambda stand for

Answer 5

Difference between observed and emitted wavelength
& - &0

& =observed wavelength
&0 = emitted wavelength

Question 6

Hubble’s law equation

Answer 6

v = H0 x d

v = recession velocity
d = distance between Earth and galaxy in question
H0 = Hubble’s parameter = 2.4x10^-18

Question 7

Equation to estimated the age of the universe (answer in seconds)

Answer 7

t = 1/H0

4.17x10^17s
=13.2 billion years

Question 8

What characteristics does a graph of recession velocity against distance have

Answer 8

Line of best fit
Through origin

Question 9

Doppler effect

Answer 9

Apparent change in wavelength and frequency when there is relative motion between a wave source and observer