Question

When two voltage of same frequency out of different phase are connected to Y and X plates of the oscilloscope, Lissajous pattern displayed on the CRO screen is shown in the figure below.
Phase difference between these two signals is _____ degree.

• A. 180
• B. 30
• C. 150
• D. 210

Answer 1

The correct option is C 150

$\sin \varphi =\frac{y_1}{y_2}=\frac{2.5}{5}=0.5$

As the major axis is in $2^{nd}and{4}^{th}$ quadrants

$\varphi =180{}^{\circ }-{\sin }^{-1}\left(0.5\right)$

$=180{}^{\circ }-30{}^{\circ }$

$=150{}^{\circ }$