A two-point source operates at a frequency of 1.0 Hz to produce an interference pattern in a ripple tank. The sources are 2.5 cm apart and the wavelength of the waves is 1.2 cm. Calculate the angles at which the nodal lines in the pattern are far from the sources. (Assume the angles are measured from the central line of the pattern). Relevant equations: dsinO = (n-1/2)(wavelength) O = angle theta my problem is, is that i can't figure out how many nodal lines there are in order to do the question. I know once i rearrange the equation i can find the angle, by the way i rearranged it to be O = sin inverse [(n-1/2)(wavelength)/d}.