1. Which type of electromagnetic radiation has the longest wavelength?
2. Which kind of photon has the highest energy?
3. An astronomer finds that the spectrum of a mysterious object shows bright emission lines. What can she conclude about the source?
A It contains cold gas.
B It is an incandescent solid body.
C It is rotating very fast..
D It contains hot, relatively tenuous gas.
E It is moving toward Earth at high speed.
4. A star's radiation is brightest at a wavelength of 450 nanometers. Its temperature is about
A 4500 K.
B 15000 K
C 1500 K
D 700 K
E 7000 K
5. If an object's spectral lines are shifted to longer wavelengths, the object is
A moving away from us.
B moving toward us.
C very hot.
D very cold.
E emitting x-rays.