Astronomy 10 Spring 2000

Worksheet #4

1. How much more energetic is an X-ray photon than a visible photon. Why can X-rays be dangerous? Why does an image of your hand taken with X-rays look different than an image take with a camera?

2. How can light be both a particle and a wave? What do each of those terms mean? Why do you think the energy of a photon depends on its wavelength (and what is this dependence)? Do you think electrons also have a wavelength?

3. Calculate the peak wavelength of the radiation from your body. Since your shirt is not very hot, how does it get its color?

What is the peak wavelength of radiation from the solar surface? The solar corona? How can each of these be observed? What sort of astronomical objects might be seen in gamma rays? Radio waves?

4. If the speed of sound is 650 mph, by what percentage does the pitch of a police siren change if it is coming down the freeway at 65 mph compared with how it sounds after it pulls the guy over? Does it sound higher or lower as it comes toward you? In order to effect the same percentage change in the color of the police lights, how fast would the car have to go?