Briefly describe the properties of a test charge and why we use them.

An electromagnetic radio wave is received by a transmitter before it is converted to a sound wave. the radio wave has a wavelength of 23,076 m and a frequency of 13,000 hz. what velocity is the wave traveling at before the transmitter converts it to a sound wave? a 1.76 m/s b 0.56 m/s c 3.31 × 102 m/s d 3.00 × 108 m/s