设\( \overrightarrow{e_{1}}\),\( \overrightarrow{e_{2}}\)为两个不共线的向量,若\( \overrightarrow{a}= \overrightarrow{e_{1}}+λ \overrightarrow{e_{2}}\),\( \overrightarrow{b}=2 \overrightarrow{e_{1}}- \overrightarrow{e_{2}}\)
\((1)\)若\( \overrightarrow{a}\)与\( \overrightarrow{b}\)共线,求实数\(λ\)的值;
\((2)\)若\( \overrightarrow{e_{1}}\),\( \overrightarrow{e_{2}}\)为互相垂直的单位向量,且\( \overrightarrow{a}⊥ \overrightarrow{b}\),求实数\(λ\)的值.