Teaching Physics with the Physics Suite

Edward F. Redish

Home | Action Research Kit| Sample Problems | Resources | Product Information

Problems Sorted by Type | Problems Sorted by Subject | Problems Sorted by Chapter in UP

Interfering electrons

A beam of mono-energetic (i.e., all having the same energy) electrons is incident on a narrow slit. A phosphorescent screen that glows when electrons hit it shows the pattern indicated at the right. Select the appropriate answer for each of the three questions below.

  1. The slit width is halved. Does the pattern
    1. get squeezed together (minima are closer together)?
    2. spread out (minima arc farther apart)?
    3. disappear?
    4. stay the same?
    5. none of the above?
  2. The energy of the electrons is doubled. Does the pattern
    1. get squeezed together (minima are closer together)?
    2. spread out (minima arc farther apart)?
    3. disappear?
    4. stay the same?
    5. none of the above?
  3. The pattern occurs because
    1. the slit is too narrow for the electrons to get through.
    2. the electrons scatter off the sides of the slit.
    3. the electron waves coming from different parts of the slit can cancel each other.
    4. the electron waves oscillate and if the oscillation is too large the electrons will strike the edge of the slit and not got through.
    5. none of the above.

Not finding what you wanted? Check the Site Map for more information.

Page last modified October 31, 2002: MP12