I want to know if a widow is required to pay zakat whether or not she has an income? Is it obligatory for her to pay zakat on the jewelry she wears?
 

Women, like men, are required to pay zakat. There is no difference between people on the basis of sex or status; Islamic duties apply to all. It makes no difference whether she is a widow, single or married. If a woman qualifies as a zakat payer, she must pay it. If not, she is not required to pay zakat.
Zakat is obligatory for anyone who possess the nisab [minimum amount on which zakat is due] which is equivalent to the value of 85 grams of gold and which must have been in the owner’s possession for one lunar year. When a person owns this amount in excess of what he needs for his living, he is required to pay zakat. He should mark the day when he first comes into possession of this amount, and this becomes his zakat date. Every year, on the same date, he should calculate what he has. If it is in excess of nisab, he must pay 2.5 % of the whole amount, not only the nisab. Certain types of property have different rates.
As for the zakat on women's jewelry, jewelry kept for personal use is non-zakatable.
And God the Almighty knows best.