1. Mars orbits the Sun with a semi-major axis of 2.3x108 km.
a. What is this distance in astronomical units?
b. What is the period of Mars' orbit in years?
2. Halley's Comet orbits the Sun once every 75 years.
a. What is the semi-major axis of the comet's orbit in astronomical units?
b. If the comet reaches a distance from the Sun of 35 AU at aphelion, what is its distance from the Sun at perihelion?
3. WILL (the University of Illinois public media service) broadcasts radio signals in both the FM and AM bands. These travel at the speed of light, 3x108 m/s.
a. WILL-FM broadcasts at a frequency of 90.0 MHz. What is the wavelength of the radio waves broadcast by WILL-FM in meters? (Hint: MHz = 106 Hz and 1 Hz is an inverse second, or 1/seconds)
b. WILL-AM broadcasts at a frequency of 580 kHz. What is the wavelength of the radio waves broadcast by WILL-AM in meters? (Hint: kHz = 103 Hz and 1 Hz is an inverse second, or 1/seconds)
4. Use Wien's Law () to determine the following:
a. The average body temperature of a human is approximately 310 K. At what wavelength (in meters) does a person glow most brightly? Your answer should be in scientific notation.
b. The largest stars in the Universe emit thermal spectra that peak at UV wavelengths of about 60x10-9m. Determine the surface temperature of these stars.