Answer:
Periodic.
Explanation:
Electromagnetic waves is a propagating medium used in all communications device to transmit data (messages) from the device of the sender to the device of the receiver.
Generally, the most commonly used electromagnetic wave technology in telecommunications is radio waves.
Radio waves can be defined as an electromagnetic wave that has its frequency ranging from 30 GHz to 300 GHz and its wavelength between 1mm and 3000m. Therefore, radio waves are a series of repetitive valleys and peaks that are typically characterized of having the longest wavelength in the electromagnetic spectrum.
Basically, as a result of radio waves having long wavelengths, they are mainly used in long-distance communications such as the carriage and transmission of data.
Generally, a fixed speed is used for the propagation of traveling waves and this speed is usually denoted with the variable "v" or sometimes "c."
Furthermore, if the waveform of a traveling wave is repeated every time at specific intervals T, it is referred to as periodic wave.
Mathematically, the period of a traveling wave is given by the formula;

Where;
T is the time measured in seconds.
Beats.
When two sound waves of different frequency approach your ear, the alternating constructive and destructive interference causes the sound to be alternatively soft and loud - a phenomenon which is called "beating" or producing beats. The beat frequency is equal to the absolute value of the difference in frequency of the two waves.
Answer:1.008 ×10^-14/rJ
Where r is the distance from.which the charge was moved through.
Explanation:
From coloumbs law
Work done =KQq/r
Where K=9×10^9
Q=7×10^-6C
q=e=1.6×10^-19C
Micro is 10^-6
W=9×10^9×7×10^-6×1.6×10^-19/r=100.8×10^-16/r=1.008×10^-14/rJ
r represent the distance through which the force was used to moved the charge through.
The ideal mechanical advantage of the pulley system is 3