What is the expiation for breaking fast due to being on a journey, or being sick, or being in a state of menstruation?

No expiation is due on the aforesaid categories, but they are obliged to make up for the missed fast. However, if any of them failed to do so while being able to, and the next Ramadhaan has come, then making up for those days is incumbent on him/her , and paying the ransom as well.

Is it permissible for the guardian, or the father of the child to hit the latter in order to teach him/her good manners?

It is permissible for the guardian to hit his/her child for teaching them good manners once they become ten years old provided that it is done mildly, harmlessly and without intimidation. Actually, such punishment is to be employed gradually i.e. after: asking, warning, and scolding. As for the teacher, he isn`t allowed to hit the student unless the latter`s father approves of it, and it is done according to necessity without intimidation, or harm.

Is everyone obligated to follow the fatwas of his country, and if we adopt the fatwas of scholars of other countries, is it considered a sin?

: It is permissible for one who do not specialize in Shari `ah sciences to apply the opinions of renowned scholars whom he trusts ,whether they be from his own country or not ,but if the scholars don`t arrive at a consensus concerning a certain matter then he must consult someone who is more knowledgeable than himself .It is preferable that you(the inquirer) specify the case of your interest ,so that we could give you a more specific answer since some scholars deliver fatwas based on atypical opinions which should not be applied no matter what .And Allah ,The Exalted, knows best.

What is the ruling of Sharia on charging one`s mobile from the plug of the university`s lecture room?