Utah State University

PHYSICS 3030

QUIZ 3

1)Star A and Star B have the same intrinsic luminosity. If an astronomer measures a greater flux (more photons per second) from Star A than from Star B, which is closer?

2. The inverse squared law works for spherical sources or point sources because the Surface Area of a sphere will scale like 1/r2 in this type of equation.

3. Which of the following wavelengths of light has the highest energy?

4. Which of the following frequencies of light has the highest energy?

5. In order to calculate the distance to a certain cepheid variable star you would need to measure the Flux (the amount of light seen per unit area) and observe the star long enough to measure the Period of the oscillation. You could then use the relationship first found by Henrietta Leavitt to calculate the intrinsic Luminosity of the star.