Two glass pates P and Q are held close and parallel to each other.A narrow beam of onochromatic light AB of intensity I is incident on plnate P ,which is partially reflected and transmitted by it. The transmitted beam DE is reflected by plate Q,which is subsequently again reflected and transmitted by the plate P as shown in Fig.6.14.

If durign a reflection,each glass plate reflects one-fourth of the light incident on it,then find the intesnstities of maxima and minima in the interference pattern produced by the two beams BC and IJ.