1. An electron has a charge ( -1.6 x 10-19 C). How many electrons would be needed to produce a net charge of (-3.2 x 10-19 C)? (a) 30, (b) 20, (c) 3, (d) 2

2.A characteristic common to sound waves and light waves is that they (a) are longitudinal waves, (b) are transverse waves, (c) transfer energy, (d) travel in a vacuum