Is a mother's prayer valid if part of her feet are uncovered during bowing (rukūʿ) or prostration (sujūd), and is her daughter's prayer behind her valid in this case?

The woman's feet are considered 'awrah' (private parts that must be covered) during prayer according to most scholars, and she must cover them. However, if the soles of her feet become uncovered during prostration, or a small part of her feet becomes uncovered during bowing, her prayer is not invalidated because this is normally a minor exposure. As a precaution, a woman should cover her hands and feet during prayer, but if she does not, her prayer is still valid. The prayer of a girl behind her mother is valid.