1.33 Only

1. 1
 
Stars typically emit the red
light of atomic hydrogen
with wavelength 656.3 nm
called the spectral line .
Compute the wavelength of
that light observed at Earth
from stars receding directly
from us with
H
3 2
1
relative speed
10 , 10 , and
10 .
v c v c
v c
 

 

Solution

2. 2

3. 3
0
0
0
0
Using
1
1
1
1
1
1
1
1
f
f
c
c








 

 





 


 


 


4. 4
3
3
3
3
3
9
3
3
9
9
1
10
1 10
656.3
1 10
10 1
10 656.3 10
10 1
10
1001
656.3 10
999
31.64
656.3 10
31.61
1.001 656.3 656.96
Case
X nm
X X m
X X m
X X m
X nm nm











 






 

5. 5
2
2
2
2
2
9
2
2
9
9
2
10
1 10
656.3
1 10
10 1
10 656.3 10
10 1
10
101
656.3 10
99
10.05
656.3 10
9.95
1.01 656.3 662.86
Case
X nm
X X m
X X m
X X m
X nm nm











 






 

6. 6
1
1
1
9
9
9
3
10
1 10
656.3
1 10
10 1
10 656.3 10
10 1
10
11
656.3 10
9
3.32
656.3 10
3.0
1.106 656.3 725.87
Case
X nm
X X m
X X m
X X m
X nm nm











 






 