A wavefront presents one, two and three HPZ at points A, B and C respectively. If the ratio of consecutive amplitudes of HPZ is 4 : 3, then the ratio of resultant intensities at these point will be

IA=R12 IB=(R1−R2)2=R121−R2R12=R121−342=R1216 IC=(R1−R2+R3)2=R121−R2R1+R3R12                                     =R121−R2R1+R3R2×R2R12 =R121−34+34×342=13162R12=169256R12 ∴   IA:IB:IC=R12:R1216:169256R12=256:16:169