GCSE    Signals    Questions 0 to 18   -->  View All  

Waves carry energy through a medium. The medium might wobble but there is no net movement.

Sine Wave

• Radio waves are part of the Electromagnetic Spectrum. They are a type of electromagnetic radiation.
• Sound waves are pressure variations in air (or any fluid) traveling through the fluid.
• This image shows a sine wave.
• It has a smooth regular shape.
• It is special because this signal contains a single frequency.
• Other wave shapes contain multiple frequencies.

Cycle

• One complete wave including one peak and one trough.

Wavelength

• The distance between one peak and the next. Any point on the wave could be used but peaks are convenient.

Frequency

• The number of cycles per second measured in Hertz (Hz).
• Frequency = 1 / Period

Period

• The time for one complete cycle to pass measured in seconds.
• Period = 1 / Frequency

Peak

• The highest point on the wave.

Trough

• The lowest point on the wave.

Displacement

• The distance the medium has moved from its mean position.

Amplitude

• This is the peak (of maximum) displacement. The size of the wave measured from the centre line usually in Volts.