Homework 11 due Wednesday, March 17

  1. The equation that relates the frequency, wavelength, and speed of a light wave-- frequency=c / wavelength--can be rewritten as c=frequency x wavelength . A friend who knows mathematics but not much astronomy or physics looks at this equation and says: "This equation tells me that the higher the frequency, the greater the wave speed c. Since visible light has a higher frequency than radio waves, this means that visible light goes faster than radio waves." How would you respond to your friend?

  2. What is a blackbody? In what way is a blackbody black? If a blackbody is black, how can it emit light?

  3. Your body temperature is 98.6o F. What kind of radiation do you predominantly emit? At what wavelength do you emit the most radiation?

  4. The human eye is most sensitive over the same wavelength range at which the Sun emits the greatest intensity of radiation. Suppose creatures were to evolve on a planet orbiting a star somewhat hotter than the Sun. To what wavelength would their eyes most likely be sensitive?

  5. Why do you suppose that ultraviolet light can cause skin cancer but ordinary visible light does not?