The Jewish or Christian wife should observe `Iddah following divorce or death of the husband, just like the Muslim woman.

The correct scholarly view regarding the `Iddah following Khul` is that it is one menstrual cycle, as is indicated by the Sunnah.

The recently-widowed woman observes mourning by refraining from adornment, perfume, kohl, skin cream (unless she has a legitimate excuse to use it), henna, and clothes dyed with safflower and saffron, if she is an adult and Muslim.

It is forbidden for a mourning woman to: 1- go out of the house except for a necessity; 2- wear perfume; 3- wear beautiful clothes; 4- apply kohl; and 5- wear jewellery.

It is permissible for the woman who is observing ‘iddah following the death of her husband or following an irrevocable divorce to go out during the day to visit her sick mother, on condition that she goes back home at night and spends the night in her own house. The basic principle regarding that is that it is permissible for her to go out during the day, if there is a need to do so. Visiting her sick mother is a need that is recognised according to Islamic teachings, because of what it involves of comforting and honouring her mother. But if the woman has received a revocable divorce, then her going out depends on the permission of her husband, because the woman who is revocably divorced is still a wife, with the same rights and duties as any other wife. Please see the details in the long answer for more information.