$2=4 \sin \omega t_{1} \Rightarrow \frac{1}{2}=\sin \omega t_{1} \Rightarrow \omega t_{1}=\frac{\pi}{6}$

and $2 \sqrt{3}=4 \sin \omega \mathrm{t}_{2} \quad \Rightarrow \frac{\sqrt{3}}{2}=\omega \mathrm{t}_{2}=\frac{2 \pi}{6}$

$\therefore \omega\left(t_{2}-t_{1}\right)=\frac{2 \pi}{6}-\frac{\pi}{6}=\frac{\pi}{6}$

$\Rightarrow \mathrm{t}_{2}-\mathrm{t}_{1}=\frac{\pi}{6} \times \frac{1}{\omega}=\frac{\pi}{6} \times \frac{\mathrm{T}}{2 \pi}=\frac{\mathrm{T}}{12}=\frac{4}{12}=\frac{1}{3} \mathrm{s}$