Maths, Physics Revision Physicss Maths Physics Physics A Level Physics Home Maths Maths Revision hut Waves Wave frequency can be seen as the  number of complete of complete waves  passing a fixed point in one second. Frequency is measured in Hertz (Hz) 1 Hertz is 1 wave per second 1 kilohertz (KHz) is 1000 Hz and is 1000 waves per second 1 megahertz is 1000000 Hertz (Mhz) 1 gigahertz is1000000000 Hertz (Ghz) The wave equation Wave speed = wavelength x frequency         a          =         b          x    c Types of wave Transverse  wave This is where The particle movement producing the wave Is at right angles to the  direction of the wave  motion Light (electromagnetic Spectrum) waves,  water waves and  secondary (S) waves in earthquakes are  transverse waves. Longitudinal wave This is where the  particle movement is parallel (in the same direction) as the wave motion. These are  called pressure waves. Sound and primary  waves (P) in  earthquakes are  longitudinal waves.