Concept: When two sinusoidal signals of the same frequency and magnitude are applied two both pairs of deflecting plates of CRO, the Lissajous pattern changes with the change of phase difference between signals applied to the CRO When 0 o or 270o o The Lissajous pattern is of the shape of an Ellipse having a major axis passing through the origin from the first quadrant to the third quadrant. When 90o o or 180o o The Lissajous Pattern is of the shape of an Ellipse having a major axis passing through the origin from the second quadrant to the fourth quadrant. Explanation: The Lissajous pattern on the screen of a CRO is an ellipse with a major axis in quadrant 1 and quadrant 3. Note: [ alt="F1 Jai 26.10.20 Pallavi D21" src="//storage.googleapis.com/tb-img/production/20/11/F1_Jai_26.10.20_Pallavi_D21.png" style="width: 320px; height: 366px;">