10.
已知向量\( \overrightarrow{OP_{1}}\),\( \overrightarrow{OP_{2}}\),\( \overrightarrow{OP_{3}}\),满足\( \overrightarrow{OP_{1}}+ \overrightarrow{OP_{2}}+ \overrightarrow{OP_{3}}=0\),且\(| \overrightarrow{OP_{1}}|=| \overrightarrow{OP_{2}}|=| \overrightarrow{OP_{3}}|=1\),则\(| \overrightarrow{P_{1}P_{2}}|=\) ______ .