Pulsars cannot be spinning white dwarfs because

Pulsars cannot be spinning white dwarfs because
 
  a. white dwarfs are not that common.
  b. white dwarfs are not dense enough.
  c. white dwarfs do not have magnetic fields.
  d. a white dwarf spinning that fast would fly apart.
  e. all of the above

Question 2

The amount of energy a photon carries depends on its wavelength.
 
  Indicate whether the statement is true or false

Question 3

In A.D. 1054, Chinese astronomers observed the appearance of a new star, whose location is now occupied by
 
  a. a pulsar.
  b. a neutron star.
  c. a supernova remnant.
  d. all of the above