1. The problem statement, all variables and given/known data Hello there, There is a question that says : ....etc....the metal is then moved towards the hardboard. In moving 6.4cm, four further maxima are observed. Calculate the wavelength of the ........etc........ Now I know how to solve it, and got the answer. (sine curve) But why do we count the amplitudes both below in the and above the axis as maxima ? I thought the maximum points are all the points above the x axis, and the minimum points are the minimum points ??! 3. The attempt at a solution All I did was : 4 max = 2[tex]\lambda[/tex] .. But these 4 maximum points are both ABOVE and BELOW the x axis for a sine curve. Then 2[tex]\lambda[/tex]=6.4cm [tex]\lambda[/tex]=3.2cm If you need me to explain my question exactly, please ask me to clarify.