## College Physics (4th Edition)

(a) Electrons were added to the balloon. (b) $3.75\times 10^{9}$ electrons were transferred to the balloon.
(a) Since the balloon acquired a negative charge, electrons were added to the balloon. (b) We can find the number of electrons that were transferred: $\frac{-0.60\times 10^{-9}~C}{-1.6\times 10^{-19}~C} = 3.75\times 10^{9}$ $3.75\times 10^{9}$ electrons were transferred to the balloon.