Modern Physics PHY 36001

Question 1.

A electromagnetic plane wave has a single wave number k.

       True
       False

Question 2.

The electromagnetic flux is given by the Poynting vector S, which has dimensions of power per unit area.

       True
       False

Question 3.

Robert Millikan discovered that when light was shown onto a metal, the amount of kinetic energy in the released electron was proportional to the frequency of the light.

       True
       False

Question 1.

The principle of superposition states that after two electromagnetic waves collide and then move apart

      a. the wave lengths of the waves will have changed but not their frequencies.
      b. the properties of each vave are the same as they were before the collision.
      c. the positions of the waves will have been shifted by a large distance.
      d. the positions of the waves are exactly shifted by the wavelength.

Question 2.

When a metal has light shined on it and electrons are released from its surface, it is called

      a. the superposition principle.
      b. electron diffraction.
      c. the photo-electric effect.
      d. Einstein's work ethic.

Question 3.

Millikan's observations regarding the experiment described above in Question 2 was that

      a. the maximum amount of kinetic energy that released electrons had was independent of the light intensity
      b. the time delay between the light first striking the metal and the first electrons released is instantaneous.
      c. the electrons are released for any value of frequency of light.
      d. all of the above
      e. just (a) and (b)
      f. just (a) and (c)
      g. just (b) and (c)