Do you think a mobil phone is necessary for a child?

You have not mentioned about the age of child. I feel that it is not good for those who are less than 15 years. Mobile phones and various applications in it, specially games, unnecessarily distract a child and it hampers their studies. Playing games in a play ground or for that matter any outdoor or indoor game is better than playing games on mobile phones.

It depends on the age of the child. A simple, basic (and cheap) mobile phone is a way of keeping in touch with home and as soon as you feel it is useful for your child to be able to contact home you should consider letting them have one. Talk with your child and make sure that you teach them how to use the phone, how to maintain it and how not to lose it!

It depends on the age. I think after age 13, yes.