Question

An inflated rubber balloon is rubbed with a wool cloth until an excess of 5.9 ✕ 10 to power of 9 electrons is on the balloon. What is the magnitude of the charge on the balloon?

Answer 1

have you heard about this one ?

Electric charge is the physical property of matter that causes it to experience a force when placed in an electromagnetic field.

Answer 2

so you know that inside this balloon there are 5,9×10^9 electrons
and you know again that one electron has a charge of
1.602×10−19 coulombs

hope these help you solve it right