If a non-Mahram sees the female’s awrah, (hair, ankle or wrist), it nullifies her wudhu. Is this correct?
بسم الله الرحمن الرحيم
(Fatwa: 328/309/N=5/1438)
Wudhu does not break if one sees the knee, back or hair of any strange woman. However, it is unlawful to see it or let others to see. Both should avoid it.
Allah knows Best!
Darul Ifta,
Darul Uloom Deoband