点\(P\)为圆\(x^{2}+y^{2}=1\)与\(x\)轴正半轴的交点,将点\(P\)沿圆周逆时针旋转至\(P'\),当转过的弧长为\(\dfrac{2}{3}π\)时,点\(P'\)的坐标为\((\quad)\)
A.\((\dfrac{1}{2},-\dfrac{\sqrt{3}}{2})\)
B.\((-\dfrac{1}{2},\dfrac{\sqrt{3}}{2})\) C.\((-\dfrac{\sqrt{3}}{2},\dfrac{1}{2})\) D.\((\dfrac{\sqrt{3}}{2},-\dfrac{1}{2})\)