Two particles $P_1$ and $P_2$ are executing SHM along the same straight line, whose equations are given $x_1=A\sin \left(\omega t+{\delta }_1\right)$ and $x_2=A\sin \left(\omega t+{\delta }_2\right)$. An observer on the ground, at t=0, observes particle $P_1$ at distance $\frac{A}{\sqrt{2}}$ moving to the right from mean position O while particle $P_2$ at $-\frac{\sqrt{3}}{2}$ A moving to the left from mean position O, as shown in figure. Find the value of ${\delta }_2-{\delta }_1$.