已知向量\(\overrightarrow{OA}=\left( \lambda \cos \alpha ,\lambda \sin \alpha \right)(λ\neq 0)\),\(\overrightarrow{OB}=\left( -\sin \beta ,\cos \beta \right)\),\(\overrightarrow{OC}=\left( 1,0 \right)\),其中\(O\)为坐标原点.
\((1)\)若\(λ=2\),\(\alpha =\dfrac{\pi }{3}\),\(β∈(0,π)\)且\(\overrightarrow{OA}\bot \overrightarrow{BC}\),求\(β\)的值;
\((2)\)若\(|\overrightarrow{AB}|\geqslant 2|\overrightarrow{OB}|\)对任意实数\(α\)、\(β\)都成立,求实数\(λ\)的取值范围.