PROPERTIES OF ELECTROMAGNETIC WAVES

Question 1

The speed of an electromagnetic wave can be expressed in terms of two
universal constants that appear in the theories of electricity and magnetism:
the ___________________________

Answer 1

• permittivity of free space ε0
• magnetic permeability of free space
  μo.

Question 2

Blue light travels through glass
at a lower speed than red light. This effect is called _________and gives rise
to rainbows and other interesting phenomena.

Answer 2

Dispersion

Question 3

This range of all
possible electromagnetic waves is
called the ______________. There is no strict lower or upper limit for electromagnetic wave frequencies, which vary over an extremely large
range.

Answer 3

• Electromagnetic Spectrum

Question 4

• ___________ have frequencies from as low as a few hertz to about ________.
• __________ are usually produced by an ________ attached to an antenna.
• A simple wire can function as an antenna, but antennas containing multiple conducting elements or shaped as _________ are usually more efficient and are much more common than those consisting of a single wire.
• The _____ in the antenna is produced by time-varying _______.
• When the AC current in an antenna oscillates with time, the moving charges in the antenna are ________as they oscillate.
• When an electric charge is accelerated, it produces ___________

Answer 4

• Radio waves, 10^9 Hz
• Radio waves, AC Circuit
• concave “dishes”
• AC Current, (oscillating) electric fields
• accelerated
• electromagnetic radiation.

Question 5

Proceeding to frequencies above the range of visible light takes us to
__________, with frequencies from about ____________.

• We cannot detect this radiation with our eyes.

Answer 5

• Ultraviolet (UV) light, 8x10^14 Hz to 1017 Hz

Question 6

• ___________ have frequencies from about __________________.

Answer 6

• X-rays, 10^17 - 10^20 Hz

Question 7

• ____________ lie at the ____________ end of the electromagnetic spectrum, with frequencies above about __________.
• Gamma rays are produced in nuclear plants and the Sun. Gamma rays also reach the Earth from sources outside
  our solar system.

Answer 7

• Gamma rays lie, high-frequency, 10^20 Hz