1. What is the frequency of a "dental" x-ray having a wavelength of 0.1Å? What is its energy?

2. The star Zeta Puppis has a temperature of 30,000K. At what wavelength is it brightest?

3. A white dwarf star has a radius of 7x108cm and a temperature of 10,000K. What is its luminosity? Compare to the Sun.

4. A radio transmitter on a spacecraft emits a signal at a frequency of 108Hz. At Earth the signal is received and noted to be at 99,970,000Hz. How fast is the spacecraft moving? Is it receding or approaching?

5. The star Vega (featured in the movie Contact) has a parallax of 0.14" (arcseconds). How long will it take light to travel there and back?