2/ What is the Sun's angular size, as seen from Mercury? Possibly useful information: A. ~1 degree B. ~1.25 degrees C. ~

[answerhappygod]

2/ What is the Sun's angular size, as seen from Mercury?
Possibly useful information:
A. ~1 degree
B. ~1.25 degrees
C. ~0.2 degrees
D. ~2 degrees
4/ What is the distance to a spiral galaxy that has an angular
diameter of 3 milliradians? (assume its physical diameter is 70,000
ly).
A. ~43 Mly
B. ~33 Mly
C. ~23 Mly
D. ~13 Mly
5/ You take a spectrum of a faraway galaxy and find that its
Hydrogen alpha line peaks at 6782 Angstroms. What is its
recessional velocity?
A. 2,000 km/s
B. 5,000 km/s
C. 7,000 km/s
D. 10,000 km/s
6/ The small-angle formula relates angular size, physical size
and distance:
θ=s/d
If you measured the angular size of an object, and knew how far
away it is, which equation would allow you to calculate its
physical size?
A. d=θ/s
B. s=d/θ
C. d=sθ
D. s=dθ