Is it permissible for a menstruating woman to sit in the mosque until the time of her exam, for fear of temptation and mingling in the streets?

The default rule is to prohibit those in a state of major ritual impurity (junub) and menstruating women from staying in the mosque, based on the Almighty’s saying: "Nor as those in a state of major ritual impurity, unless passing through, until you have bathed" (Quran 4:43). This is the view of the majority of scholars. Some scholars permit it, but the relied-upon opinion is that of the majority, which is prohibition. The questioner should cover her face and avoid temptation, and seek a safe place for study outside the mosque. If that is not possible and she genuinely fears harm to her religion, wealth, or honor, then it is permissible for her to stay in the mosque to avert that harm.